A key aspect of the imaging capability of radar systems is the angular resolution, which is determined by the aperture size of the antenna array. Therefore technologies such as MIMO and especially radar networks consisting of multiple independent MIMO radar sensors seek to maximize the virtual aperture size. Depending on the range and velocity resolution of the MIMO radar network, multistatic aspects must be accounted for. So far, those multistatic effects were seen as errors, which must be compensated for in order to restore the classical DoA properties of the virtual aperture, described by the narrowband beam pattern. This paper shows that new virtual aperture designs with larger antenna spacings are possible while still preserving the angular ambiguity range of smaller antenna spacings, as long as the multistatic effects of distributed radar networks, namely radar networks whose virtual aperture is large in comparison to the range resolution, are correctly accounted for. The larger antenna element spacing enables larger aperture sizes leading to higher angular resolution. This paper illustrates that the well-known, Fourier Tranformation-based signal processing is unable to exploit this potential of distributed radar networks, and an computationally efficient approximated matched filter is proposed. This article presents a signal model for distributed radar networks, suitable signal processing, and a comparison to the well-known Fourier Transformation-based signal processing for compact radar networks. Both the signal model and the proposed signal processing are verified by measurements with a radar sensor network composed of 2 MIMO radar sensors operating in the automotive frequency range of $76 ,mathrm{G}mathrm{Hz},mathrm{to}, 81 ,mathrm{G}mathrm{Hz}$ providing 64 virtual channels with a range resolution of $0.03 ,mathrm{m}$ . The virtual aperture size of the radar network is ${sim }0.5 ,mathrm{m}$ with virtual antenna spacing of twice the wavelength, but the proposed signal processing still allows unambiguous DoA estimation within the full $180 ,mathrm{^{circ }}$ range.
雷达系统成像能力的一个关键方面是角度分辨率，它由天线阵列的孔径大小决定。因此，MIMO 等技术，特别是由多个独立 MIMO 雷达传感器组成的雷达网络，都在寻求最大化虚拟孔径尺寸。根据 MIMO 雷达网络的测距和速度分辨率，必须考虑多静态因素。迄今为止，这些多静态效应被视为误差，必须对其进行补偿，以恢复窄带波束模式所描述的虚拟孔径的经典 DoA 特性。本文表明，只要正确考虑到分布式雷达网（即虚拟孔径与测距分辨率相比较大的雷达网）的多静态效应，就有可能采用较大天线间距的新虚拟孔径设计，同时仍能保持较小天线间距的角模糊范围。天线元件间距越大，孔径也就越大，角度分辨率也就越高。本文说明了众所周知的基于傅立叶变换的信号处理无法利用分布式雷达网络的这一潜力，并提出了一种计算效率高的近似匹配滤波器。本文介绍了分布式雷达网络的信号模型、合适的信号处理方法，并与著名的基于傅里叶变换的紧凑型雷达网络信号处理方法进行了比较。该信号模型和所提出的信号处理方法都通过一个雷达传感器网络的测量得到了验证，该雷达传感器网络由2个MIMO雷达传感器组成，工作在汽车频率范围为76 mathrm{G}mathrm{Hz} mathrm{to}, 81 mathrm{G} mathrm{Hz}$ ，提供64个虚拟信道，量程分辨率为0.03 mathrm{m}$ 。雷达网络的虚拟孔径大小为${sim }0.5 mathrm{m}$ ，虚拟天线间距为波长的两倍，但拟议的信号处理仍可在 180 mathrm{^{circ }}$ 的完整范围内进行明确的 DoA 估计。
{"title":"On Distributed Radar Networks: Signal Model, Analysis, and Signal Processing","authors":"Vinzenz Janoudi;Pirmin Schoeder;Timo Grebner;Nils Appenrodt;Juergen Dickmann;Christian Waldschmidt","doi":"10.1109/JMW.2024.3414471","DOIUrl":"https://doi.org/10.1109/JMW.2024.3414471","url":null,"abstract":"A key aspect of the imaging capability of radar systems is the angular resolution, which is determined by the aperture size of the antenna array. Therefore technologies such as MIMO and especially radar networks consisting of multiple independent MIMO radar sensors seek to maximize the virtual aperture size. Depending on the range and velocity resolution of the MIMO radar network, multistatic aspects must be accounted for. So far, those multistatic effects were seen as errors, which must be compensated for in order to restore the classical DoA properties of the virtual aperture, described by the narrowband beam pattern. This paper shows that new virtual aperture designs with larger antenna spacings are possible while still preserving the angular ambiguity range of smaller antenna spacings, as long as the multistatic effects of distributed radar networks, namely radar networks whose virtual aperture is large in comparison to the range resolution, are correctly accounted for. The larger antenna element spacing enables larger aperture sizes leading to higher angular resolution. This paper illustrates that the well-known, Fourier Tranformation-based signal processing is unable to exploit this potential of distributed radar networks, and an computationally efficient approximated matched filter is proposed. This article presents a signal model for distributed radar networks, suitable signal processing, and a comparison to the well-known Fourier Transformation-based signal processing for compact radar networks. Both the signal model and the proposed signal processing are verified by measurements with a radar sensor network composed of 2 MIMO radar sensors operating in the automotive frequency range of \u0000<inline-formula><tex-math>$76 ,mathrm{G}mathrm{Hz},mathrm{to}, 81 ,mathrm{G}mathrm{Hz}$</tex-math></inline-formula>\u0000 providing 64 virtual channels with a range resolution of \u0000<inline-formula><tex-math>$0.03 ,mathrm{m}$</tex-math></inline-formula>\u0000. The virtual aperture size of the radar network is \u0000<inline-formula><tex-math>${sim }0.5 ,mathrm{m}$</tex-math></inline-formula>\u0000 with virtual antenna spacing of twice the wavelength, but the proposed signal processing still allows unambiguous DoA estimation within the full \u0000<inline-formula><tex-math>$180 ,mathrm{^{circ }}$</tex-math></inline-formula>\u0000 range.","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"4 3","pages":"329-347"},"PeriodicalIF":6.9,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10587002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141631082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-03DOI: 10.1109/JMW.2024.3413791
Chatchai Chokchai;Yoshiki Sugimoto;Kunio Sakakibara;Makoto Yamazaki;Henry Abu Diawuo;Nobuyoshi Kikuma
This paper proposes a broadband single-ended line-to-waveguide transition that covers the 240–300 GHz band. The transition comprises a tapered grounded coplanar waveguide (GCPW) feed line, inserted from the narrow wall of the waveguide exciting a modified V-shaped patch located at the center of the waveguide. Broadband operation is achieved via multiple resonances of the modified V-shaped patch, a double-stacked rectangular patch, and cavity within the multi-layer substrates. The transition geometries are optimized via electromagnetic simulations using the finite element method. The transition design is successful within fabrication limitations in the terahertz frequency band. Subsequent evaluations of transition performance are conducted through measurements and simulations. Experimental results show a bandwidth below −10 dB for S 11 spanning 71.5 GHz. Furthermore, the measured insertion loss remains consistent at 2.5 dB at the center frequency of 275 GHz.
本文提出了一种覆盖 240-300 GHz 波段的宽带单端线路到波导过渡装置。该过渡装置包括一条锥形接地共面波导（GCPW）馈电线，从波导窄壁插入，刺激位于波导中心的改进型 V 形贴片。通过改进型 V 形贴片、双层矩形贴片和多层基底内空腔的多重共振，实现宽带运行。通过使用有限元法进行电磁模拟，对过渡几何形状进行了优化。过渡设计在太赫兹频段的制造限制范围内取得了成功。随后通过测量和模拟对过渡性能进行了评估。实验结果表明，S11 的带宽低于 -10 dB，频率跨度为 71.5 GHz。此外，在 275 GHz 的中心频率上，测量到的插入损耗始终保持在 2.5 dB。
{"title":"Broadband GCPW-to-Waveguide Transition in Multi-Layer Dielectric Substrates With Modified V-Shaped and Double Patch in 270 GHz Band","authors":"Chatchai Chokchai;Yoshiki Sugimoto;Kunio Sakakibara;Makoto Yamazaki;Henry Abu Diawuo;Nobuyoshi Kikuma","doi":"10.1109/JMW.2024.3413791","DOIUrl":"https://doi.org/10.1109/JMW.2024.3413791","url":null,"abstract":"This paper proposes a broadband single-ended line-to-waveguide transition that covers the 240–300 GHz band. The transition comprises a tapered grounded coplanar waveguide (GCPW) feed line, inserted from the narrow wall of the waveguide exciting a modified V-shaped patch located at the center of the waveguide. Broadband operation is achieved via multiple resonances of the modified V-shaped patch, a double-stacked rectangular patch, and cavity within the multi-layer substrates. The transition geometries are optimized via electromagnetic simulations using the finite element method. The transition design is successful within fabrication limitations in the terahertz frequency band. Subsequent evaluations of transition performance are conducted through measurements and simulations. Experimental results show a bandwidth below −10 dB for \u0000<italic>S</i>\u0000<sub>11</sub>\u0000 spanning 71.5 GHz. Furthermore, the measured insertion loss remains consistent at 2.5 dB at the center frequency of 275 GHz.","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"4 3","pages":"537-547"},"PeriodicalIF":6.9,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10584085","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141630998","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-03DOI: 10.1109/JMW.2024.3414130
Kunchen Zhao;Christian Elmiger;Dimitra Psychogiou
A new class of highly-miniaturized “dome”-shaped 3D bandpass filters (BPFs) are presented. Size reduction is achieved by using: i) capacitively-loaded hemispherical resonators that are significantly smaller than a conventional spherical resonator, ii) stereolithography apparatus (SLA)-based 3D printing facilitating monolithic integration, and by iii) vertically-stacked resonators. A comprehensive design methodology is provided and applied to the realization of high order BPFs. An RF excitation scheme allowing for wideband out-of-band suppression is also proposed. For proof-of-concept validation purposes, a second- and a third-order BPF prototypes operating at 5.8 GHz, and a compact vertically-stacked second-order BPF were designed, manufactured, and tested. The measurement results exhibit the following characteristics: second-order BPF: center frequency f c = 5.8 GHz, fractional bandwidth (FBW) = 5.5%, effective quality factor ( Q eff ) = 890, 20 dB upper stopband suppression up to 10.14 GHz (1.7.3 f c ); third-order BPF: f c = 5.8 GHz, FBW = 6.5%, Q eff = 1,230, and 20 dB upper stopband suppression up to 10.1 GHz (1.74 f c ); vertically-stacked second-order BPF: f c = 5.9 GHz, FBW = 10.0%, Q eff = 720, and 20 dB upper stopband suppression up to 8.9 GHz (1.5 f c )
{"title":"Monolithically-Integrated 3D Printed Bandpass Filters Using Highly-Miniaturized Dome-Shaped Resonators","authors":"Kunchen Zhao;Christian Elmiger;Dimitra Psychogiou","doi":"10.1109/JMW.2024.3414130","DOIUrl":"https://doi.org/10.1109/JMW.2024.3414130","url":null,"abstract":"A new class of highly-miniaturized “dome”-shaped 3D bandpass filters (BPFs) are presented. Size reduction is achieved by using: i) capacitively-loaded hemispherical resonators that are significantly smaller than a conventional spherical resonator, ii) stereolithography apparatus (SLA)-based 3D printing facilitating monolithic integration, and by iii) vertically-stacked resonators. A comprehensive design methodology is provided and applied to the realization of high order BPFs. An RF excitation scheme allowing for wideband out-of-band suppression is also proposed. For proof-of-concept validation purposes, a second- and a third-order BPF prototypes operating at 5.8 GHz, and a compact vertically-stacked second-order BPF were designed, manufactured, and tested. The measurement results exhibit the following characteristics: second-order BPF: center frequency \u0000<italic>f</i>\u0000<sub>c</sub>\u0000 = 5.8 GHz, fractional bandwidth (FBW) = 5.5%, effective quality factor (\u0000<italic>Q</i>\u0000<sub>eff</sub>\u0000) = 890, 20 dB upper stopband suppression up to 10.14 GHz (1.7.3\u0000<italic>f</i>\u0000<sub>c</sub>\u0000); third-order BPF: \u0000<italic>f</i>\u0000<sub>c</sub>\u0000 = 5.8 GHz, FBW = 6.5%, \u0000<italic>Q</i>\u0000<sub>eff</sub>\u0000 = 1,230, and 20 dB upper stopband suppression up to 10.1 GHz (1.74\u0000<italic>f</i>\u0000<sub>c</sub>\u0000); vertically-stacked second-order BPF: \u0000<italic>f</i>\u0000<sub>c</sub>\u0000 = 5.9 GHz, FBW = 10.0%, \u0000<italic>Q</i>\u0000<sub>eff</sub>\u0000 = 720, and 20 dB upper stopband suppression up to 8.9 GHz (1.5\u0000<italic>f</i>\u0000<sub>c</sub>\u0000)","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"4 3","pages":"548-557"},"PeriodicalIF":6.9,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10584097","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141630966","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-01DOI: 10.1109/JMW.2024.3412415
Tobias T. Braun;Jan Schöpfel;Christian Bredendiek;Juan Jose Forero B.;Nils Pohl
Harmonic radar systems are highly effective at distinguishing specific targets from surrounding clutter. Therefore, the reception of a tag response, conventionally at the second harmonic, is utilized. Thus, necessitating two bands with that specific spacing allocated to the same application. Among others, this is not the case for automotive, where tag-based detection of vulnerable road users in city traffic has shown promising results. Therefore, we introduce the novel nonlinear radar category of inharmonic radar. It is based on fractional multiplication, to enable a wider range of possible factors. Specifically, the automotive band at 76–81 GHz is connected with the 134–141 GHz frequency range by a factor of 1.75. The realized system achieves a clutter rejection of 60 dB, which is investigated in detail regarding influences of the inharmonic approach. Detection of the corresponding tag is successfully achieved up to a distance of 28 m with compliance for automotive radar, while no significant spectral purity degradation is caused by the unique frequency conversion.
{"title":"Introducing Inharmonic Radar: Tag Detection in the Automotive Bands of Present and Future at 76–81/134–141 GHz via Fractional Multiplication","authors":"Tobias T. Braun;Jan Schöpfel;Christian Bredendiek;Juan Jose Forero B.;Nils Pohl","doi":"10.1109/JMW.2024.3412415","DOIUrl":"https://doi.org/10.1109/JMW.2024.3412415","url":null,"abstract":"Harmonic radar systems are highly effective at distinguishing specific targets from surrounding clutter. Therefore, the reception of a tag response, conventionally at the second harmonic, is utilized. Thus, necessitating two bands with that specific spacing allocated to the same application. Among others, this is not the case for automotive, where tag-based detection of vulnerable road users in city traffic has shown promising results. Therefore, we introduce the novel nonlinear radar category of inharmonic radar. It is based on fractional multiplication, to enable a wider range of possible factors. Specifically, the automotive band at 76–81 GHz is connected with the 134–141 GHz frequency range by a factor of 1.75. The realized system achieves a clutter rejection of 60 dB, which is investigated in detail regarding influences of the inharmonic approach. Detection of the corresponding tag is successfully achieved up to a distance of 28 m with compliance for automotive radar, while no significant spectral purity degradation is caused by the unique frequency conversion.","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"4 3","pages":"473-485"},"PeriodicalIF":6.9,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10579935","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141630914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-21DOI: 10.1109/JMW.2024.3407712
Giulia Sacco;Maxim Zhadobov
With the massive deployment of 5G worldwide the entire population is expected to be exposed to millimeter waves (mmWs), representing new frequencies recently introduced into our environmental electromagnetic (EM) background. From this perspective, the interactions between mmWs and human tissues have been actively investigated during the past few years at various levels. This article reviews recent publications in this field, from macro- to micro-scale. The role of different parameters is considered, including the characteristics of the impinging field (angle of incidence, polarization, and source type), age, presence of clothing, curvature of the body surface, and inter-individual differences. Finally, findings on recent micro-dosimetry studies at mmWs are summarized highlighting the impact of micro-scale heterogeneity related to the presence of skin sub-structures and organelles inside the cells on the local power distribution and heating.
{"title":"Physical Interactions Between Millimeter Waves and Human Body: From Macro- to Micro-Scale","authors":"Giulia Sacco;Maxim Zhadobov","doi":"10.1109/JMW.2024.3407712","DOIUrl":"https://doi.org/10.1109/JMW.2024.3407712","url":null,"abstract":"With the massive deployment of 5G worldwide the entire population is expected to be exposed to millimeter waves (mmWs), representing new frequencies recently introduced into our environmental electromagnetic (EM) background. From this perspective, the interactions between mmWs and human tissues have been actively investigated during the past few years at various levels. This article reviews recent publications in this field, from macro- to micro-scale. The role of different parameters is considered, including the characteristics of the impinging field (angle of incidence, polarization, and source type), age, presence of clothing, curvature of the body surface, and inter-individual differences. Finally, findings on recent micro-dosimetry studies at mmWs are summarized highlighting the impact of micro-scale heterogeneity related to the presence of skin sub-structures and organelles inside the cells on the local power distribution and heating.","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"4 3","pages":"318-328"},"PeriodicalIF":6.9,"publicationDate":"2024-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10568574","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141630958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A low-cost electrically-switched focused beam charging system based on a reconfigurable phase-change cascaded feed network is introduced for wireless power transfer application. To realize the reconfigurable feed network, we theoretically decomposed the dynamic focusing phase distribution into two independent terms: a linear phase shift and a quadratic term. A focused aperture-coupled patch array antenna with static focused beam is fabricated to achieve the quadratic term. Different linear phase shifts are achieved by using designed electronic switching module to control the beam port status of Rotman lens, enabling to tilt the static focused beam in the desired direction. Based on full-wave simulation and near-field focusing measurement, we analyzed the dynamic focusing performance of generated focused beam with different beam ports excited at 5.758 GHz in detail. Besides, a LED lighting demo experiment for proposed system is carried out for visually displaying the generated dynamic focused beam. The simulation and experiment results indicate that the generated dynamic focused beam tilts as the excitation state of the beam port changes, and its focal spot can be also observed well on the focal plane. The architecture of proposed focused beam system eliminates the need for expensive phase shifters, resulting in a significant reduction in system costs.
本文介绍了一种基于可重构相变级联馈电网络的低成本电开关聚焦光束充电系统，用于无线功率传输应用。为实现可重构馈电网络，我们从理论上将动态聚焦相位分布分解为两个独立项：线性相移和二次项。为了实现二次项，我们制作了具有静态聚焦波束的聚焦孔径耦合贴片阵列天线。通过使用设计的电子开关模块来控制罗特曼透镜的波束端口状态，实现不同的线性相移，从而使静态聚焦波束向所需方向倾斜。基于全波仿真和近场聚焦测量，我们详细分析了在 5.758 GHz 频率下激发不同束口所产生的聚焦光束的动态聚焦性能。此外，为了直观地显示所产生的动态聚焦光束，我们还对所提出的系统进行了 LED 照明演示实验。模拟和实验结果表明，生成的动态聚焦光束会随着光束端口激励状态的变化而倾斜，其焦斑在焦平面上也能很好地观察到。拟议的聚焦光束系统结构无需使用昂贵的移相器，从而大大降低了系统成本。
{"title":"Realization of Electrically-Switched Dynamic Focused Beam Charging System With a Reconfigurable Phase-Change Cascaded Feed Network for Wireless Power Transfer","authors":"Wenyi Shao;Bo Yang;Shinichiro Horiuchi;Naoki Shinohara;Minoru Furukawa","doi":"10.1109/JMW.2024.3412029","DOIUrl":"https://doi.org/10.1109/JMW.2024.3412029","url":null,"abstract":"A low-cost electrically-switched focused beam charging system based on a reconfigurable phase-change cascaded feed network is introduced for wireless power transfer application. To realize the reconfigurable feed network, we theoretically decomposed the dynamic focusing phase distribution into two independent terms: a linear phase shift and a quadratic term. A focused aperture-coupled patch array antenna with static focused beam is fabricated to achieve the quadratic term. Different linear phase shifts are achieved by using designed electronic switching module to control the beam port status of Rotman lens, enabling to tilt the static focused beam in the desired direction. Based on full-wave simulation and near-field focusing measurement, we analyzed the dynamic focusing performance of generated focused beam with different beam ports excited at 5.758 GHz in detail. Besides, a LED lighting demo experiment for proposed system is carried out for visually displaying the generated dynamic focused beam. The simulation and experiment results indicate that the generated dynamic focused beam tilts as the excitation state of the beam port changes, and its focal spot can be also observed well on the focal plane. The architecture of proposed focused beam system eliminates the need for expensive phase shifters, resulting in a significant reduction in system costs.","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"4 3","pages":"348-359"},"PeriodicalIF":6.9,"publicationDate":"2024-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10559481","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141630988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Radar networks offer the possibility to overcome the limitations of single sensors. However, without coherent signal processing, the full potential of radar networks cannot be exploited. Therefore, the synchronization of independent radar sensors is crucial in order to mitigate performance degradation due to frequency deviations of uncoupled reference oscillators. Systematically derived synchronization criteria for coupling-induced errors such as sampling frequency offset (SFO), carrier frequency offset (CFO) and symbol timing offset (STO) of uncoupled orthogonal frequency-division multiplexing (OFDM) radar sensors enable to determine hardware specifications, such as the required reference oscillator frequency stability. This aids in the design of digital radar networks and ensures error-free signal processing in advance. The concept of deriving said criteria is applicable to other modulation types used for digital radar sensors. Additionally, signal processing-based error estimation and correction methods are presented. By exploiting standard radar images, namely range profiles and range-Doppler images, the proposed methods estimate and correct any occurring SFO, CFO and STO. Furthermore, by applying the signal processing synchronization methods, they allow for a more lenient radar network design. Measurements using a 77 GHz digital radar demonstrator verify the derived criteria and error estimation and correction methods.
{"title":"Uncoupled Digital Radars Creating a Coherent Sensor Network","authors":"Julian Aguilar;David Werbunat;Vinzenz Janoudi;Christina Bonfert;Christian Waldschmidt","doi":"10.1109/JMW.2024.3405633","DOIUrl":"https://doi.org/10.1109/JMW.2024.3405633","url":null,"abstract":"Radar networks offer the possibility to overcome the limitations of single sensors. However, without coherent signal processing, the full potential of radar networks cannot be exploited. Therefore, the synchronization of independent radar sensors is crucial in order to mitigate performance degradation due to frequency deviations of uncoupled reference oscillators. Systematically derived synchronization criteria for coupling-induced errors such as sampling frequency offset (SFO), carrier frequency offset (CFO) and symbol timing offset (STO) of uncoupled orthogonal frequency-division multiplexing (OFDM) radar sensors enable to determine hardware specifications, such as the required reference oscillator frequency stability. This aids in the design of digital radar networks and ensures error-free signal processing in advance. The concept of deriving said criteria is applicable to other modulation types used for digital radar sensors. Additionally, signal processing-based error estimation and correction methods are presented. By exploiting standard radar images, namely range profiles and range-Doppler images, the proposed methods estimate and correct any occurring SFO, CFO and STO. Furthermore, by applying the signal processing synchronization methods, they allow for a more lenient radar network design. Measurements using a 77 GHz digital radar demonstrator verify the derived criteria and error estimation and correction methods.","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"4 3","pages":"459-472"},"PeriodicalIF":6.9,"publicationDate":"2024-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10557779","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141630912","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-13DOI: 10.1109/JMW.2024.3406919
TIM PFAHLER;ANDRE SCHEDER;ANNA BRIDIER;MATHIAS NAGEL;MARTIN VOSSIEK
This paper presents an ultra-broadband, low-loss, flexible liquid crystal polymer substrate-to-substrate interconnect with a bandwidth of more than 130 GHz. The transition discontinuity was minimized by maintaining both the reference impedance and the electromagnetic field conformity across the transition from alumina substrate to flip-chip foil. Therefore, more than 600 $mu$ m long flexible flip-chip interconnects can be realized for bridging millimeter-wave sub-modules and enabling ultra-broadband heterogeneous system design with a measured return loss of above 20 dB. Furthermore, the interconnect can realize ramp interconnections between monolithic microwave integrated circuits or substrates with different substrate heights due to the flexible foil substrate. Minimum parasitic radiation at the transition is realized through a closely spaced signal-to-ground connection. Furthermore, the robustness of the proposed interconnect against lateral misalignment in the assembly is presented through simulation and measurement. An outstanding insertion loss of less than 0.3 dB per transition over a bandwidth of more than 130 GHz is shown.
{"title":"A Foil Flip-Chip Interconnect With an Ultra-Broadband Bandwidth of 130 GHz and Beyond for Heterogeneous High-End System Designs","authors":"TIM PFAHLER;ANDRE SCHEDER;ANNA BRIDIER;MATHIAS NAGEL;MARTIN VOSSIEK","doi":"10.1109/JMW.2024.3406919","DOIUrl":"https://doi.org/10.1109/JMW.2024.3406919","url":null,"abstract":"This paper presents an ultra-broadband, low-loss, flexible liquid crystal polymer substrate-to-substrate interconnect with a bandwidth of more than 130 GHz. The transition discontinuity was minimized by maintaining both the reference impedance and the electromagnetic field conformity across the transition from alumina substrate to flip-chip foil. Therefore, more than 600 \u0000<inline-formula><tex-math>$mu$</tex-math></inline-formula>\u0000m long flexible flip-chip interconnects can be realized for bridging millimeter-wave sub-modules and enabling ultra-broadband heterogeneous system design with a measured return loss of above 20 dB. Furthermore, the interconnect can realize ramp interconnections between monolithic microwave integrated circuits or substrates with different substrate heights due to the flexible foil substrate. Minimum parasitic radiation at the transition is realized through a closely spaced signal-to-ground connection. Furthermore, the robustness of the proposed interconnect against lateral misalignment in the assembly is presented through simulation and measurement. An outstanding insertion loss of less than 0.3 dB per transition over a bandwidth of more than 130 GHz is shown.","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"4 3","pages":"404-415"},"PeriodicalIF":6.9,"publicationDate":"2024-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10557560","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141631084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-12DOI: 10.1109/JMW.2024.3404832
Zeina Al Masri;Ahmad Jabri;Youssef Tawk;Joseph Costantine
This paper presents a groove gap waveguide structure designed to serve as a feeding network for dual circularly polarized antenna arrays in the millimeter wave spectrum (28-32 GHz). The proposed structure comprises four groove gap waveguide elements arranged in a cross-shaped configuration. A turnstile integrated into the middle position of the structure divides the incoming RF signal into these four waveguide elements. Four matching posts are incorporated at the end of the various groove gap waveguide elements to route each corresponding RF signal to four WR-28 waveguide sections. These four sections form the output ports of the feeding network. The appropriate design of the pin distributions along the four groove gap elements allows the entire feeding network to achieve a specific phase shift between the output ports. As a proof of concept, the proposed feeding network is connected to a dual circularly polarized antenna array composed of four sub-arrays. Two of these sub-arrays emit right-handed circularly polarized waves, while the other two are designed to provide left-handed circularly polarized waves. A prototype of the feeding network demonstrates its ability to produce the needed circularly polarized radiation for a given distribution of the pins along the various groove gap elements. The results show that the feeding network can achieve an insertion loss as low as 0.55 dB with a good impedance matching across the entire operational bandwidth. In addition, when the fabricated feeding network is connected to the dual-circularly polarized antenna prototype, a maximum realized gain of 15.14 dBic is obtained.
{"title":"A Groove Gap Waveguide Feeding Network for Dual-Circularly Polarized Antenna Arrays","authors":"Zeina Al Masri;Ahmad Jabri;Youssef Tawk;Joseph Costantine","doi":"10.1109/JMW.2024.3404832","DOIUrl":"https://doi.org/10.1109/JMW.2024.3404832","url":null,"abstract":"This paper presents a groove gap waveguide structure designed to serve as a feeding network for dual circularly polarized antenna arrays in the millimeter wave spectrum (28-32 GHz). The proposed structure comprises four groove gap waveguide elements arranged in a cross-shaped configuration. A turnstile integrated into the middle position of the structure divides the incoming RF signal into these four waveguide elements. Four matching posts are incorporated at the end of the various groove gap waveguide elements to route each corresponding RF signal to four WR-28 waveguide sections. These four sections form the output ports of the feeding network. The appropriate design of the pin distributions along the four groove gap elements allows the entire feeding network to achieve a specific phase shift between the output ports. As a proof of concept, the proposed feeding network is connected to a dual circularly polarized antenna array composed of four sub-arrays. Two of these sub-arrays emit right-handed circularly polarized waves, while the other two are designed to provide left-handed circularly polarized waves. A prototype of the feeding network demonstrates its ability to produce the needed circularly polarized radiation for a given distribution of the pins along the various groove gap elements. The results show that the feeding network can achieve an insertion loss as low as 0.55 dB with a good impedance matching across the entire operational bandwidth. In addition, when the fabricated feeding network is connected to the dual-circularly polarized antenna prototype, a maximum realized gain of 15.14 dBic is obtained.","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"4 3","pages":"512-520"},"PeriodicalIF":6.9,"publicationDate":"2024-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10555289","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141631081","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-04DOI: 10.1109/JMW.2024.3405018
João Louro;Luís C. Nunes;Filipe M. Barradas;Pedro M. Cabral;José C. Pedro
This work originates from the realization that, in a transformed impedance thru-reflect-line (TRL) calibration, the sensitivity to random measurement errors is affected by impedance discrepancies between the impedance transformer and the device-under-test (DUT). Through a thorough exploration that includes theoretical analysis, simulations and TRL measurements, this study establishes that the accuracy of de-embedding operations on a transformed impedance medium is intricately tied to the difference between the Thevenin impedance seen from the DUT-side of the launcher and the DUT impedance. A noteworthy finding is that minimizing this difference enhances the resilience of the de-embedding process against random measurement errors, being advantageous for precision modeling techniques, and demonstrating the importance of considering those concepts when designing an access structure to a DUT.
{"title":"The Impact of a Taper Impedance Transformation on the TRL De-Embedding Error","authors":"João Louro;Luís C. Nunes;Filipe M. Barradas;Pedro M. Cabral;José C. Pedro","doi":"10.1109/JMW.2024.3405018","DOIUrl":"https://doi.org/10.1109/JMW.2024.3405018","url":null,"abstract":"This work originates from the realization that, in a transformed impedance thru-reflect-line (TRL) calibration, the sensitivity to random measurement errors is affected by impedance discrepancies between the impedance transformer and the device-under-test (DUT). Through a thorough exploration that includes theoretical analysis, simulations and TRL measurements, this study establishes that the accuracy of de-embedding operations on a transformed impedance medium is intricately tied to the difference between the Thevenin impedance seen from the DUT-side of the launcher and the DUT impedance. A noteworthy finding is that minimizing this difference enhances the resilience of the de-embedding process against random measurement errors, being advantageous for precision modeling techniques, and demonstrating the importance of considering those concepts when designing an access structure to a DUT.","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"4 3","pages":"389-403"},"PeriodicalIF":6.9,"publicationDate":"2024-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10547231","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141630959","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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