Pub Date : 2023-09-01DOI: 10.1109/JMW.2023.3307630
Alex Pitt;Gautam Jindal;Kevin Morris;Tommaso Cappello
This article presents a design methodology for an asymmetrical Doherty Power Amplifier (DPA) which achieves a high average efficiency at back off across its operating bandwidth. It is shown that by combining continuous modes with post matching techniques, it is possible to achieve excellent efficiency performance whilst maintaining broadband operation. Analysis is provided on how the knee effect can reduce the effective potential efficiency of Class J and Continuous Inverse Class F modes. An optimum combination of $2text{nd}$ and $3text{rd}$ harmonic impedances is then proposed for the carrier PA which can minimise this knee effect impact on efficiency performance. Also, it is shown how the drain supply can be used to improve the bandwidth over which an intrinsic optimum load can be maintained. Based on this analysis, a simple iterative design procedure is then presented which can be directly implemented with standard RF design tools. This design procedure is then verified in the design and manufacture of a prototype DPA using the Wolfspeed CG2H40010F GaN HEMT. The realised PA operates between 2.1 and 3.2 GHz with a peak power output of between 43.9 and 44.5 dBm. The PA achieves a high average drain efficiency of 64.7 % at 8–9 dB of back off. The DPA has been tested with and without digital pre-distortion (DPD) by considering a 60 MHz LTE OFDM signal with 9 dB peak-to-average power ratio (PAPR). When DPD is enabled, the presented DPA achieves a drain efficiency of between 52.1–64.3 with an adjacent channel power ratio (ACPR) of between −42.2– −44.1 dB over the bandwidth of 2.1–3.2 GHz.
{"title":"A Broadband Asymmetrical Doherty Power Amplifier With Optimized Continuous Mode Harmonic Impedances","authors":"Alex Pitt;Gautam Jindal;Kevin Morris;Tommaso Cappello","doi":"10.1109/JMW.2023.3307630","DOIUrl":"10.1109/JMW.2023.3307630","url":null,"abstract":"This article presents a design methodology for an asymmetrical Doherty Power Amplifier (DPA) which achieves a high average efficiency at back off across its operating bandwidth. It is shown that by combining continuous modes with post matching techniques, it is possible to achieve excellent efficiency performance whilst maintaining broadband operation. Analysis is provided on how the knee effect can reduce the effective potential efficiency of Class J and Continuous Inverse Class F modes. An optimum combination of \u0000<inline-formula><tex-math>$2text{nd}$</tex-math></inline-formula>\u0000 and \u0000<inline-formula><tex-math>$3text{rd}$</tex-math></inline-formula>\u0000 harmonic impedances is then proposed for the carrier PA which can minimise this knee effect impact on efficiency performance. Also, it is shown how the drain supply can be used to improve the bandwidth over which an intrinsic optimum load can be maintained. Based on this analysis, a simple iterative design procedure is then presented which can be directly implemented with standard RF design tools. This design procedure is then verified in the design and manufacture of a prototype DPA using the Wolfspeed CG2H40010F GaN HEMT. The realised PA operates between 2.1 and 3.2 GHz with a peak power output of between 43.9 and 44.5 dBm. The PA achieves a high average drain efficiency of 64.7 % at 8–9 dB of back off. The DPA has been tested with and without digital pre-distortion (DPD) by considering a 60 MHz LTE OFDM signal with 9 dB peak-to-average power ratio (PAPR). When DPD is enabled, the presented DPA achieves a drain efficiency of between 52.1–64.3 with an adjacent channel power ratio (ACPR) of between −42.2– −44.1 dB over the bandwidth of 2.1–3.2 GHz.","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"3 4","pages":"1120-1133"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/9171629/10271404/10237343.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47298577","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 : 2023-09-01DOI: 10.1109/JMW.2023.3305180
Lu Qian;Yeshodhara Baskaran;Matthias Krödel;César Miquel España;Laurent Pambaguian;Talal Skaik;Yi Wang
This article for the first time presents a high-Q cavity resonator manufactured using carbon-fiber reinforced silicon carbide (SiC) ceramic composite material HB-Cesic. This composite has attractive properties of low coefficient of thermal expansion comparable to Invar, low density similar to aluminum, and high thermal conductivity. Its manufacturing process enabled by machining and joining renders useful design flexibility. A high-Q spherical resonator has been used as an example in this investigation. Two resonators, one monolithic version and the other one based on split-block structure have been experimented. The end-to-end processes from machining, assembly or joining, to high-conductivity coating for both structures, have been demonstrated. The RF performance of the resonators and their variation with temperature have been measured. A quality factor of over 10000 has been achieved for both resonators at 11.483 GHz. The measured high thermal stability of the resonator correlates very well with the prediction. This work establishes the feasibility of using HB-Cesic in microwave resonators and paves the way for further development and verification programme for more complex passive microwave devices such as filters and multiplexers for space applications.
{"title":"Lightweight, High-Q and High Temperature Stability Microwave Cavity Resonators Using Carbon-Fiber Reinforced Silicon-Carbide Ceramic Composite","authors":"Lu Qian;Yeshodhara Baskaran;Matthias Krödel;César Miquel España;Laurent Pambaguian;Talal Skaik;Yi Wang","doi":"10.1109/JMW.2023.3305180","DOIUrl":"10.1109/JMW.2023.3305180","url":null,"abstract":"This article for the first time presents a high-Q cavity resonator manufactured using carbon-fiber reinforced silicon carbide (SiC) ceramic composite material HB-Cesic. This composite has attractive properties of low coefficient of thermal expansion comparable to Invar, low density similar to aluminum, and high thermal conductivity. Its manufacturing process enabled by machining and joining renders useful design flexibility. A high-Q spherical resonator has been used as an example in this investigation. Two resonators, one monolithic version and the other one based on split-block structure have been experimented. The end-to-end processes from machining, assembly or joining, to high-conductivity coating for both structures, have been demonstrated. The RF performance of the resonators and their variation with temperature have been measured. A quality factor of over 10000 has been achieved for both resonators at 11.483 GHz. The measured high thermal stability of the resonator correlates very well with the prediction. This work establishes the feasibility of using HB-Cesic in microwave resonators and paves the way for further development and verification programme for more complex passive microwave devices such as filters and multiplexers for space applications.","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"3 4","pages":"1230-1236"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/9171629/10271404/10237345.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43019710","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}
This article reports a wide-band power divider with ultra-wide harmonic suppression. The filtering power divider consists of a Wilkinson power divider and a filter merged into a single structure. For filtering purposes, a novel suppressor cell is designed using resonators of various shapes. The power divider exhibits an operational frequency of 1.64 GHz, encompassing a fractional bandwidth (FBW) of 57 percent, ranging from 1.151 GHz to 2.08 GHz. Notably, it effectively suppresses a total of 24 harmonics, attaining a rejection level exceeding −15 dB. The measured in-band isolation, input return loss, insertion loss, and output return loss are determined at 1.64 GHz to be −23 dB, −36 dB, −3.03 dB, and −18 dB, respectively. These results showcase the superior performance of the proposed design compared to existing state-of-the-art solutions.
{"title":"A Wideband RF Power Divider With Ultra-Wide Harmonics Suppression","authors":"Sikandar Abbas;Moazam Maqsood;Nosherwan Shoaib;Muhammad Qasim Mehmood;Muhammad Zubair;Yehia Massoud","doi":"10.1109/JMW.2023.3307654","DOIUrl":"10.1109/JMW.2023.3307654","url":null,"abstract":"This article reports a wide-band power divider with ultra-wide harmonic suppression. The filtering power divider consists of a Wilkinson power divider and a filter merged into a single structure. For filtering purposes, a novel suppressor cell is designed using resonators of various shapes. The power divider exhibits an operational frequency of 1.64 GHz, encompassing a fractional bandwidth (FBW) of 57 percent, ranging from 1.151 GHz to 2.08 GHz. Notably, it effectively suppresses a total of 24 harmonics, attaining a rejection level exceeding −15 dB. The measured in-band isolation, input return loss, insertion loss, and output return loss are determined at 1.64 GHz to be −23 dB, −36 dB, −3.03 dB, and −18 dB, respectively. These results showcase the superior performance of the proposed design compared to existing state-of-the-art solutions.","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"3 4","pages":"1248-1257"},"PeriodicalIF":0.0,"publicationDate":"2023-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/9171629/10271404/10235265.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46228061","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 : 2023-08-25DOI: 10.1109/JMW.2023.3307297
Lingzhen Zeng;Cheuk-Yu Edward Tong;Scott N. Paine
Cryogenic isolators play an important role in low-noise receiver systems widely employed in millimeter and submillimeter telescopes. To enable a significantly wider Intermediate Frequency (IF) bandwidth, there is strong demand for a wideband, low-loss isolator in modern facilities like the Submillimeter Array (SMA) and Atacama Large Millimeter/submillimeter Array (ALMA). In this article, we present a novel cryogenic edge-mode isolator that incorporates an innovative circuit design. Operating at a cryogenic temperature of 4 K, this isolator delivers unprecedented performance, covering a frequency range from 4 GHz to 22 GHz. It exhibits insertion loss of less than 1 dB, together with return loss below -15 dB. In particular, it provides an isolation better than 17 dB across most of the band, a significant improvement over the previous generation of edge-mode isolators. This new isolator design is suitable for a wide array of low-noise receiver applications, from radio-astronomy to quantum computing.
{"title":"A Low-Insertion Loss Cryogenic Edge-Mode Isolator With 18 GHz Bandwidth","authors":"Lingzhen Zeng;Cheuk-Yu Edward Tong;Scott N. Paine","doi":"10.1109/JMW.2023.3307297","DOIUrl":"10.1109/JMW.2023.3307297","url":null,"abstract":"Cryogenic isolators play an important role in low-noise receiver systems widely employed in millimeter and submillimeter telescopes. To enable a significantly wider Intermediate Frequency (IF) bandwidth, there is strong demand for a wideband, low-loss isolator in modern facilities like the Submillimeter Array (SMA) and Atacama Large Millimeter/submillimeter Array (ALMA). In this article, we present a novel cryogenic edge-mode isolator that incorporates an innovative circuit design. Operating at a cryogenic temperature of 4 K, this isolator delivers unprecedented performance, covering a frequency range from 4 GHz to 22 GHz. It exhibits insertion loss of less than 1 dB, together with return loss below -15 dB. In particular, it provides an isolation better than 17 dB across most of the band, a significant improvement over the previous generation of edge-mode isolators. This new isolator design is suitable for a wide array of low-noise receiver applications, from radio-astronomy to quantum computing.","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"3 4","pages":"1258-1266"},"PeriodicalIF":0.0,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/9171629/10271404/10230855.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41423826","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 : 2023-08-03DOI: 10.1109/JMW.2023.3296594
Christoph Birkenhauer;Georg Körner;Patrick Stief;Gerhard Hamberger;Matthias Beer;Christian Carlowitz;Martin Vossiek
Radar target simulators are not only a critical tool for verifying and testing radar systems but also play an important role in supporting the development of self-driving cars. Advances in radar sensors and techniques raise the required specifications for these units, increasing their complexity and cost. This article presents a novel and universal concept for radar target simulators that addresses these issues by responding only to the transmitted signal of a radar sensor during a fraction of the time, therefore modulating the average of the signal. This offers advantages for three independent use cases, which may be combined. First, the dynamic range and resolution of simulated target echo power can be improved even for existing systems. Second, the simulation of multiangle scenarios with a single backend is possible with this approach. Finally, hardware complexity and power consumption can be reduced. The proposed concept is examined extensively for frequency-modulated continuous wave radar, and design decisions are made. The theoretical considerations are validated with measurements with a real radar target simulator showing an improvement of up to $30 ,mathrm{dB}$ in the dynamic range with no observable negative side effects.
{"title":"A Simple and Versatile Concept to Improve Dynamic Range and Enable Target Angle Adaptability in Radar Target Simulators","authors":"Christoph Birkenhauer;Georg Körner;Patrick Stief;Gerhard Hamberger;Matthias Beer;Christian Carlowitz;Martin Vossiek","doi":"10.1109/JMW.2023.3296594","DOIUrl":"10.1109/JMW.2023.3296594","url":null,"abstract":"Radar target simulators are not only a critical tool for verifying and testing radar systems but also play an important role in supporting the development of self-driving cars. Advances in radar sensors and techniques raise the required specifications for these units, increasing their complexity and cost. This article presents a novel and universal concept for radar target simulators that addresses these issues by responding only to the transmitted signal of a radar sensor during a fraction of the time, therefore modulating the average of the signal. This offers advantages for three independent use cases, which may be combined. First, the dynamic range and resolution of simulated target echo power can be improved even for existing systems. Second, the simulation of multiangle scenarios with a single backend is possible with this approach. Finally, hardware complexity and power consumption can be reduced. The proposed concept is examined extensively for frequency-modulated continuous wave radar, and design decisions are made. The theoretical considerations are validated with measurements with a real radar target simulator showing an improvement of up to \u0000<inline-formula><tex-math>$30 ,mathrm{dB}$</tex-math></inline-formula>\u0000 in the dynamic range with no observable negative side effects.","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"3 4","pages":"1109-1119"},"PeriodicalIF":0.0,"publicationDate":"2023-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/9171629/10271404/10207805.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45970405","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 : 2023-08-02DOI: 10.1109/JMW.2023.3289979
Giovanni Ghione;Marco Pirola
In the design of amplifier stages based on unconditionally stable linear active two-ports, the amplifier gain can be maximized through simultaneous conjugate matching with passive loads at the input and output ports. Conversely, the optimization of linear amplifiers based on conditionally stable active devices requires a trade-off between gain, stability margin, input/output port mismatch and (for low-noise amplifiers) noise figure. Exploiting potentially in-band unstable devices can be advantageous in the design of open-loop low-noise amplifiers, since the in-band stabilization with input resistors is well known to negatively affect the amplifier minimum noise figure. Within this framework, the article derives a lower bound to the input and output mismatch of non unconditionally stable linear two-ports. The minumum mismatch is shown to only depend, in a simple way, on the stability factor $K$ and on the assumed mismatch ratio between the two ports. The minimum mismatch condition can be implemented by cascading the active, potentially in-band unstable two-port with two (input and output) reactive matching sections. The application of the theory to the design of low-noise amplifier open-loop stages based on conditionally stable active devices is discussed through CAD examples.
{"title":"On the Lower Bound to the Input and Output Mismatch of Conditionally Stable Linear Two-Ports","authors":"Giovanni Ghione;Marco Pirola","doi":"10.1109/JMW.2023.3289979","DOIUrl":"10.1109/JMW.2023.3289979","url":null,"abstract":"In the design of amplifier stages based on unconditionally stable linear active two-ports, the amplifier gain can be maximized through simultaneous conjugate matching with passive loads at the input and output ports. Conversely, the optimization of linear amplifiers based on conditionally stable active devices requires a trade-off between gain, stability margin, input/output port mismatch and (for low-noise amplifiers) noise figure. Exploiting potentially in-band unstable devices can be advantageous in the design of open-loop low-noise amplifiers, since the in-band stabilization with input resistors is well known to negatively affect the amplifier minimum noise figure. Within this framework, the article derives a lower bound to the input and output mismatch of non unconditionally stable linear two-ports. The minumum mismatch is shown to only depend, in a simple way, on the stability factor \u0000<inline-formula><tex-math>$K$</tex-math></inline-formula>\u0000 and on the assumed mismatch ratio between the two ports. The minimum mismatch condition can be implemented by cascading the active, potentially in-band unstable two-port with two (input and output) reactive matching sections. The application of the theory to the design of low-noise amplifier open-loop stages based on conditionally stable active devices is discussed through CAD examples.","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"3 4","pages":"1166-1176"},"PeriodicalIF":0.0,"publicationDate":"2023-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/9171629/10271404/10201920.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47057608","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 : 2023-07-31DOI: 10.1109/JMW.2023.3294106
Shengjia Wu;Jiro Hirokawa;Takashi Tomura;Nelson J. G. Fonseca
This article provides for the first time a detailed discussion of the optimal assignment of adjacent output phase differences in terms of matrix performance out of all possible combinations in generalized one-dimensional parallel switching matrices with four beams. In this specific case, the topology of the proposed matrix reduces to that of a single-layer Butler matrix, connecting hybrid couplers and crossovers with adequate phase shifters. The values of the phase shift required are dependent on the assignment of the output phase differences, which in turn is shown to have an impact on the radiation characteristics of the linear array fed by such networks when imposing constraints on the matrix layout for a more generic implementation. The configuration having the smallest phase difference with reference to the transmission phase of a straight waveguide with the same length as the coupled region of the crossover is chosen and compared with the conventional well-known Butler matrix. The two matrix configurations are implemented using post-wall waveguides designed to operate over the band 20 GHz – 24 GHz. The prototypes are manufactured and tested, using transitions to standard waveguide WR42. The measured results confirm the benefits of the identified optimal adjacent phase difference assignment in terms of transmission coefficients, reflection coefficients, phase differences between adjacent output ports, and frequency dependence of the array factor. These results will also benefit the design of larger generalized one-dimensional parallel switching matrices.
{"title":"Optimal Adjacent Output Phase Difference Assignments in One-Dimensional Parallel Switching Matrices With Four Beams","authors":"Shengjia Wu;Jiro Hirokawa;Takashi Tomura;Nelson J. G. Fonseca","doi":"10.1109/JMW.2023.3294106","DOIUrl":"10.1109/JMW.2023.3294106","url":null,"abstract":"This article provides for the first time a detailed discussion of the optimal assignment of adjacent output phase differences in terms of matrix performance out of all possible combinations in generalized one-dimensional parallel switching matrices with four beams. In this specific case, the topology of the proposed matrix reduces to that of a single-layer Butler matrix, connecting hybrid couplers and crossovers with adequate phase shifters. The values of the phase shift required are dependent on the assignment of the output phase differences, which in turn is shown to have an impact on the radiation characteristics of the linear array fed by such networks when imposing constraints on the matrix layout for a more generic implementation. The configuration having the smallest phase difference with reference to the transmission phase of a straight waveguide with the same length as the coupled region of the crossover is chosen and compared with the conventional well-known Butler matrix. The two matrix configurations are implemented using post-wall waveguides designed to operate over the band 20 GHz – 24 GHz. The prototypes are manufactured and tested, using transitions to standard waveguide WR42. The measured results confirm the benefits of the identified optimal adjacent phase difference assignment in terms of transmission coefficients, reflection coefficients, phase differences between adjacent output ports, and frequency dependence of the array factor. These results will also benefit the design of larger generalized one-dimensional parallel switching matrices.","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"3 4","pages":"1199-1211"},"PeriodicalIF":0.0,"publicationDate":"2023-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/9171629/10271404/10197603.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46561544","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 : 2023-07-10DOI: 10.1109/JMW.2023.3285825
Ping Lu;Mahmoud Wagih;George Goussetis;Naoki Shinohara;Chaoyun Song
In recent years, microwave wireless power transmission (MWPT) has emerged as a promising technology for supplying energy by receiving radiative power without wires and converting it into DC power. A high transmission efficiency is crucial for improving the performance of MWPT systems. To address the challenge of propagation loss, beam synthesis using transmitting antennas has gained significant attention, resulting in several synthesis methods becoming available, including whisper beams, flat-top beams, non-diffractive beams, supergain/superdirective beams, focused beams and adaptive beamforming technique such as time reversal methods. This comprehensive review covers these advanced beam synthesis techniques for MWPT transmitters and provides a detailed comparison of different synthesized beams. The article includes an in-depth discussion on current designs and existing technological challenges, as well as suggestions for future research directions. Although beam synthesis can substantially improve the transmission efficiency, the overall power transfer efficiency of the entire MWPT system still requires improvement as the performance, including impedance matching, is currently only considered at a component level and not at a system level. Furthermore, when using advanced beam synthesis techniques, the engineering and implementation challenges of high power (≥kW) and long-distance (≥km) MWPT become significant issues due to the high cost and large size involved. The review concludes that existing technologies for synthesized beams still require significant long-term efforts to meet the realistic engineering requirements for achieving highly efficient MWPT systems. The joint utilization of beam synthesis techniques and comprehensive system matching/optimization is identified as a research direction with the potential to realize highly efficient MWPT systems, offering foreseeable impacts in both terrestrial and space-based MWPT applications. This review serves as a solid foundation for the design of transmitter antennas in long-distance, high-power MWPT systems, and furthermore provides novel insights for future designs of highly efficient MWPT systems.
{"title":"A Comprehensive Survey on Transmitting Antenna Systems With Synthesized Beams for Microwave Wireless Power Transmission","authors":"Ping Lu;Mahmoud Wagih;George Goussetis;Naoki Shinohara;Chaoyun Song","doi":"10.1109/JMW.2023.3285825","DOIUrl":"10.1109/JMW.2023.3285825","url":null,"abstract":"In recent years, microwave wireless power transmission (MWPT) has emerged as a promising technology for supplying energy by receiving radiative power without wires and converting it into DC power. A high transmission efficiency is crucial for improving the performance of MWPT systems. To address the challenge of propagation loss, beam synthesis using transmitting antennas has gained significant attention, resulting in several synthesis methods becoming available, including whisper beams, flat-top beams, non-diffractive beams, supergain/superdirective beams, focused beams and adaptive beamforming technique such as time reversal methods. This comprehensive review covers these advanced beam synthesis techniques for MWPT transmitters and provides a detailed comparison of different synthesized beams. The article includes an in-depth discussion on current designs and existing technological challenges, as well as suggestions for future research directions. Although beam synthesis can substantially improve the transmission efficiency, the overall power transfer efficiency of the entire MWPT system still requires improvement as the performance, including impedance matching, is currently only considered at a component level and not at a system level. Furthermore, when using advanced beam synthesis techniques, the engineering and implementation challenges of high power (≥kW) and long-distance (≥km) MWPT become significant issues due to the high cost and large size involved. The review concludes that existing technologies for synthesized beams still require significant long-term efforts to meet the realistic engineering requirements for achieving highly efficient MWPT systems. The joint utilization of beam synthesis techniques and comprehensive system matching/optimization is identified as a research direction with the potential to realize highly efficient MWPT systems, offering foreseeable impacts in both terrestrial and space-based MWPT applications. This review serves as a solid foundation for the design of transmitter antennas in long-distance, high-power MWPT systems, and furthermore provides novel insights for future designs of highly efficient MWPT systems.","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"3 4","pages":"1081-1101"},"PeriodicalIF":0.0,"publicationDate":"2023-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/9171629/10271404/10177162.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42431930","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}
The rapid progress in semiconductor technology has vastly boosted the development of terahertz sources and receivers in terms of compactness, reliability, operation frequency, and output power. In this manuscript, we report on the latest achievements in terahertz sources and receivers and provide a comprehensive overview of their working principles and applications in THz systems.
{"title":"Terahertz Sources and Receivers: From the Past to the Future","authors":"Sumer Makhlouf;Oleg Cojocari;Martin Hofmann;Tadao Nagatsuma;Sascha Preu;Nils Weimann;Heinz-Wilhelm Hübers;Andreas Stöhr","doi":"10.1109/JMW.2023.3282875","DOIUrl":"10.1109/JMW.2023.3282875","url":null,"abstract":"The rapid progress in semiconductor technology has vastly boosted the development of terahertz sources and receivers in terms of compactness, reliability, operation frequency, and output power. In this manuscript, we report on the latest achievements in terahertz sources and receivers and provide a comprehensive overview of their working principles and applications in THz systems.","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"3 3","pages":"894-912"},"PeriodicalIF":0.0,"publicationDate":"2023-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/9171629/10175027/10175031.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44231513","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 : 2023-07-06DOI: 10.1109/JMW.2023.3285610
Christian Schuessler;Marcel Hoffmann;Martin Vossiek
This paper introduces a method based on a deep neural network (DNN) that is perfectly capable of processing radar data from extremely thinned radar apertures. The proposed DNN processing can provide both aliasing-free radar imaging and super-resolution. The results are validated by measuring the detection performance on realistic simulation data and by evaluating the Point-Spread-function (PSF) and the target-separation performance on measured point-like targets. Also, a qualitative evaluation of a typical automotive scene is conducted. It is shown that this approach can outperform state-of-the-art subspace algorithms and also other existing machine learning solutions. The presented results suggest that machine learning approaches trained with sufficiently sophisticated virtual input data are a very promising alternative to compressed sensing and subspace approaches in radar signal processing. The key to this performance is that the DNN is trained using realistic simulation data that perfectly mimic a given sparse antenna radar array hardware as the input. As ground truth, ultra-high resolution data from an enhanced virtual radar are simulated. Contrary to other work, the DNN utilizes the complete radar cube and not only the antenna channel information at certain range-Doppler detections. After training, the proposed DNN is capable of sidelobe- and ambiguity-free imaging. It simultaneously delivers nearly the same resolution and image quality as would be achieved with a fully occupied array.
{"title":"Super-Resolution Radar Imaging With Sparse Arrays Using a Deep Neural Network Trained With Enhanced Virtual Data","authors":"Christian Schuessler;Marcel Hoffmann;Martin Vossiek","doi":"10.1109/JMW.2023.3285610","DOIUrl":"10.1109/JMW.2023.3285610","url":null,"abstract":"This paper introduces a method based on a deep neural network (DNN) that is perfectly capable of processing radar data from extremely thinned radar apertures. The proposed DNN processing can provide both aliasing-free radar imaging and super-resolution. The results are validated by measuring the detection performance on realistic simulation data and by evaluating the Point-Spread-function (PSF) and the target-separation performance on measured point-like targets. Also, a qualitative evaluation of a typical automotive scene is conducted. It is shown that this approach can outperform state-of-the-art subspace algorithms and also other existing machine learning solutions. The presented results suggest that machine learning approaches trained with sufficiently sophisticated virtual input data are a very promising alternative to compressed sensing and subspace approaches in radar signal processing. The key to this performance is that the DNN is trained using realistic simulation data that perfectly mimic a given sparse antenna radar array hardware as the input. As ground truth, ultra-high resolution data from an enhanced virtual radar are simulated. Contrary to other work, the DNN utilizes the complete radar cube and not only the antenna channel information at certain range-Doppler detections. After training, the proposed DNN is capable of sidelobe- and ambiguity-free imaging. It simultaneously delivers nearly the same resolution and image quality as would be achieved with a fully occupied array.","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"3 3","pages":"980-993"},"PeriodicalIF":0.0,"publicationDate":"2023-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/9171629/10175027/10175032.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46924568","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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