Pub Date : 2012-12-01DOI: 10.1109/APMC.2012.6421900
T. Shen, Zhijing Hu, T. Wong
To properly account for space-charge effects, transport models can be employed in the analysis of charge motions within semiconductor nanostructures. In this paper, we present the analysis and computations of internal charge and field distributions in a semiconductor nanoplate. Analytical and numerical simulation results reveal space-charge waves excited in the plate as the bulk plasma frequency is approached, which is in the terahertz band. A lumped equivalent circuit is developed to characterize the dispersion properties and to facilitate the consideration of more complex structures based on aggregates of nanoplates for potential circuit and waveguide applications in the terahertz frequency range.
{"title":"Terahertz space-charge interactions in a semiconductor nanoplate","authors":"T. Shen, Zhijing Hu, T. Wong","doi":"10.1109/APMC.2012.6421900","DOIUrl":"https://doi.org/10.1109/APMC.2012.6421900","url":null,"abstract":"To properly account for space-charge effects, transport models can be employed in the analysis of charge motions within semiconductor nanostructures. In this paper, we present the analysis and computations of internal charge and field distributions in a semiconductor nanoplate. Analytical and numerical simulation results reveal space-charge waves excited in the plate as the bulk plasma frequency is approached, which is in the terahertz band. A lumped equivalent circuit is developed to characterize the dispersion properties and to facilitate the consideration of more complex structures based on aggregates of nanoplates for potential circuit and waveguide applications in the terahertz frequency range.","PeriodicalId":359125,"journal":{"name":"2012 Asia Pacific Microwave Conference Proceedings","volume":"161 11","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114115050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/APMC.2012.6421480
Hyunji Koo, Bonhoon Koo, Songcheol Hong
A 24 GHz Power amplifier (PA) with high efficiency designed in the 0.13-μm CMOS process is presented. The proposed adaptive-bias circuit is used to improve the efficiency. The quiescent power consumption is 79.2 mW, which is improved by 53.8mW, compared to that of the optimized fixed-biased (0.6V) PA. Power added efficiency (PAE) and output power (POUT) at a 1-dB-gain-compression-power (P1dB) is 15.6 % and 13.3 dBm, respectively. This result is improved as much as 4% and 1.2dB, compare to that of PA with fixed-bias of 0.6V.
{"title":"Highly efficient 24-GHz CMOS linear power amplifier with an adaptive bias circuit","authors":"Hyunji Koo, Bonhoon Koo, Songcheol Hong","doi":"10.1109/APMC.2012.6421480","DOIUrl":"https://doi.org/10.1109/APMC.2012.6421480","url":null,"abstract":"A 24 GHz Power amplifier (PA) with high efficiency designed in the 0.13-μm CMOS process is presented. The proposed adaptive-bias circuit is used to improve the efficiency. The quiescent power consumption is 79.2 mW, which is improved by 53.8mW, compared to that of the optimized fixed-biased (0.6V) PA. Power added efficiency (PAE) and output power (POUT) at a 1-dB-gain-compression-power (P1dB) is 15.6 % and 13.3 dBm, respectively. This result is improved as much as 4% and 1.2dB, compare to that of PA with fixed-bias of 0.6V.","PeriodicalId":359125,"journal":{"name":"2012 Asia Pacific Microwave Conference Proceedings","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114359438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/APMC.2012.6421493
Li-Ting Chen, Jia‐Fu Tsai, Ming-Jyun Hou, J. Row
A design for dual-band circularly polarized (CP) antennas is presented. The antenna is composed of two concentric shorted annular slots, and each slot can generate circular polarization radiation at its one wavelength resonant mode or one-and-a-half wavelength resonant mode by varying the position of the shorted section. When the one wavelength mode of the outer slot and the one-and-a-half wavelength mode of the inner slot are simultaneously excited, the antenna has two CP operating frequencies with a large frequency ratio. A small frequency ratio can also be achieved when the outer and inner annular slots are operated at the one-and-a-half wavelength mode and one wavelength mode, respectively. Two examples with the frequency ratios of 1.05 and 2 are designed and implemented. Details of the experimental results are shown.
{"title":"Dual-band circularly polarized annular ring slot antenna","authors":"Li-Ting Chen, Jia‐Fu Tsai, Ming-Jyun Hou, J. Row","doi":"10.1109/APMC.2012.6421493","DOIUrl":"https://doi.org/10.1109/APMC.2012.6421493","url":null,"abstract":"A design for dual-band circularly polarized (CP) antennas is presented. The antenna is composed of two concentric shorted annular slots, and each slot can generate circular polarization radiation at its one wavelength resonant mode or one-and-a-half wavelength resonant mode by varying the position of the shorted section. When the one wavelength mode of the outer slot and the one-and-a-half wavelength mode of the inner slot are simultaneously excited, the antenna has two CP operating frequencies with a large frequency ratio. A small frequency ratio can also be achieved when the outer and inner annular slots are operated at the one-and-a-half wavelength mode and one wavelength mode, respectively. Two examples with the frequency ratios of 1.05 and 2 are designed and implemented. Details of the experimental results are shown.","PeriodicalId":359125,"journal":{"name":"2012 Asia Pacific Microwave Conference Proceedings","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114878971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/APMC.2012.6421852
T. Izumi, H. Arai
EMC(Electro Magnetic Compatibility) tests have been inevitable for electronic products of recent years. Most of the products are tested in anechoic chamber or open site, but in an experiment, it is susceptible to error caused by reflections from the wall because absolute free space could not be achieved with absorber. Then an evaluation value for constructing a better condition of anechoic chamber in which the error is reduced, is required. To design high performance measurement environment and anechoic chamber, we propose an evaluation value using the phase difference between direct wave and reflected wave. The value is introduced with the investigation of the error source by ray-tracing method. The results using proposed value for locating the transmitting point show that it is possible to improve the measurement environment by calculation. Moreover this indicates that the better design of anechoic chambers can be obtained by this value.
{"title":"A novel design method of EMC anechoic chamber using phase and magnitude deviation","authors":"T. Izumi, H. Arai","doi":"10.1109/APMC.2012.6421852","DOIUrl":"https://doi.org/10.1109/APMC.2012.6421852","url":null,"abstract":"EMC(Electro Magnetic Compatibility) tests have been inevitable for electronic products of recent years. Most of the products are tested in anechoic chamber or open site, but in an experiment, it is susceptible to error caused by reflections from the wall because absolute free space could not be achieved with absorber. Then an evaluation value for constructing a better condition of anechoic chamber in which the error is reduced, is required. To design high performance measurement environment and anechoic chamber, we propose an evaluation value using the phase difference between direct wave and reflected wave. The value is introduced with the investigation of the error source by ray-tracing method. The results using proposed value for locating the transmitting point show that it is possible to improve the measurement environment by calculation. Moreover this indicates that the better design of anechoic chambers can be obtained by this value.","PeriodicalId":359125,"journal":{"name":"2012 Asia Pacific Microwave Conference Proceedings","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126463113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/APMC.2012.6421915
Chi-Chang Lin, Yuh-Jing Hwang, S. Srikanth
A broadband 800-MHz short backfire antenna (SBA) integrated with a cryogenic vacuum chamber is designed for astronomical applications. The cryostat offers the low-temperature condition to front-end components because of low-noise demands for the astronomy observations. In order to overcome the impacts from the cryostat, the SBA adopts a pair of concentric sleeves to replace the conventional double-discs design. It features a dual-mode response and enhances the bandwidth. The simulated results show the VSWR less than 2.2 and the gain of 11-15 dBi over the band of 700-945 MHz.
{"title":"Short backfire antenna with concentric sleeves for highly sensitive radio astronomical receivers","authors":"Chi-Chang Lin, Yuh-Jing Hwang, S. Srikanth","doi":"10.1109/APMC.2012.6421915","DOIUrl":"https://doi.org/10.1109/APMC.2012.6421915","url":null,"abstract":"A broadband 800-MHz short backfire antenna (SBA) integrated with a cryogenic vacuum chamber is designed for astronomical applications. The cryostat offers the low-temperature condition to front-end components because of low-noise demands for the astronomy observations. In order to overcome the impacts from the cryostat, the SBA adopts a pair of concentric sleeves to replace the conventional double-discs design. It features a dual-mode response and enhances the bandwidth. The simulated results show the VSWR less than 2.2 and the gain of 11-15 dBi over the band of 700-945 MHz.","PeriodicalId":359125,"journal":{"name":"2012 Asia Pacific Microwave Conference Proceedings","volume":"111 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128028936","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/APMC.2012.6421913
J. Tsai, Yih-Chien Chen, Chung-Yen Wu
In this paper, the simulation and measurement results of dual-band planar inverted-F antenna for application in ISM, HIPERLAN, UNII, and WiMAX bands were presented. The dual-band planar inverted-F antenna was fabricated on a FR4 substrate. The lower band was associated with the longer open strip while the upper band was associated with the shorter open strip of the proposed dual-band planar inverted-F antenna. The proposed antenna had good agreement between the measurement and simulation results in return loss. The proposed antenna had a 10 dB return loss with bandwidth 350 MHz (2, 294-2,644 MHz) in the lower band and 1,237 MHz (4,694-5,931 MHz) in the upper band. The proposed dual-band planar inverted-F antenna covered the ISM, HIPERLAN, UNII, and WiMAX bands. The maximum antenna efficiencies are -0.83 dB and -1.49 dB at 2.45 and 5.45 GHz, respectively.
{"title":"Dual-band planar inverted-F antenna for application in ISM, HIPERLAN, UNII, and WiMAX","authors":"J. Tsai, Yih-Chien Chen, Chung-Yen Wu","doi":"10.1109/APMC.2012.6421913","DOIUrl":"https://doi.org/10.1109/APMC.2012.6421913","url":null,"abstract":"In this paper, the simulation and measurement results of dual-band planar inverted-F antenna for application in ISM, HIPERLAN, UNII, and WiMAX bands were presented. The dual-band planar inverted-F antenna was fabricated on a FR4 substrate. The lower band was associated with the longer open strip while the upper band was associated with the shorter open strip of the proposed dual-band planar inverted-F antenna. The proposed antenna had good agreement between the measurement and simulation results in return loss. The proposed antenna had a 10 dB return loss with bandwidth 350 MHz (2, 294-2,644 MHz) in the lower band and 1,237 MHz (4,694-5,931 MHz) in the upper band. The proposed dual-band planar inverted-F antenna covered the ISM, HIPERLAN, UNII, and WiMAX bands. The maximum antenna efficiencies are -0.83 dB and -1.49 dB at 2.45 and 5.45 GHz, respectively.","PeriodicalId":359125,"journal":{"name":"2012 Asia Pacific Microwave Conference Proceedings","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125999911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/APMC.2012.6421855
Ci Huang, Yijun Feng, Lin-Xiao Wu, Junmin Zhao, T. Jiang
In this paper, we propose a novel chiral metamaterial structure that enables asymmetric electromagnetic (EM) waves propagation. The metamaterial is composed of two metallic sheets with periodic split-ring resonator structures on both sides of a dielectric substrate. By full-wave EM simulations and free space measurements, strong diode-like asymmetric transmission of linearly polarized EM waves through such a thin metamaterial slab, has been demonstrated in the microwave band. It allows transmission of linearly polarized EM wave in one direction, while no transmission in the opposite direction. Such phenomenon is due to the strong cross-polarized conversion in the chiral slab with a thickness of one-fifteenth the operational wavelength that could rotate the linear polarization of the incident waves to its orthogonal polarization.
{"title":"Diode-like asymmetric transmission of linearly polarized waves through twisted split-ring metamaterial structure","authors":"Ci Huang, Yijun Feng, Lin-Xiao Wu, Junmin Zhao, T. Jiang","doi":"10.1109/APMC.2012.6421855","DOIUrl":"https://doi.org/10.1109/APMC.2012.6421855","url":null,"abstract":"In this paper, we propose a novel chiral metamaterial structure that enables asymmetric electromagnetic (EM) waves propagation. The metamaterial is composed of two metallic sheets with periodic split-ring resonator structures on both sides of a dielectric substrate. By full-wave EM simulations and free space measurements, strong diode-like asymmetric transmission of linearly polarized EM waves through such a thin metamaterial slab, has been demonstrated in the microwave band. It allows transmission of linearly polarized EM wave in one direction, while no transmission in the opposite direction. Such phenomenon is due to the strong cross-polarized conversion in the chiral slab with a thickness of one-fifteenth the operational wavelength that could rotate the linear polarization of the incident waves to its orthogonal polarization.","PeriodicalId":359125,"journal":{"name":"2012 Asia Pacific Microwave Conference Proceedings","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122222680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/APMC.2012.6421899
Theng Huat Gan, E. L. Tan
This paper presents the current source implementations for the fundamental second-order accurate split-step unite-difference time-domain (SS2-FDTD) method. To improve efficiency, the SS2-FDTD method is formulated in the most fundamental form with the simplest and most concise right-hand sides free of matrix operators. The consistent and symmetrical current source implementations of the two-substep alternating-direction-implicit (ADI) FDTD method are extended and investigated for the three-substep SS2-FDTD method. Numerical results are presented to compare various current source implementations for the fundamental SS2-FDTD method.
{"title":"Current source implementations for fundamental SS2-FDTD method","authors":"Theng Huat Gan, E. L. Tan","doi":"10.1109/APMC.2012.6421899","DOIUrl":"https://doi.org/10.1109/APMC.2012.6421899","url":null,"abstract":"This paper presents the current source implementations for the fundamental second-order accurate split-step unite-difference time-domain (SS2-FDTD) method. To improve efficiency, the SS2-FDTD method is formulated in the most fundamental form with the simplest and most concise right-hand sides free of matrix operators. The consistent and symmetrical current source implementations of the two-substep alternating-direction-implicit (ADI) FDTD method are extended and investigated for the three-substep SS2-FDTD method. Numerical results are presented to compare various current source implementations for the fundamental SS2-FDTD method.","PeriodicalId":359125,"journal":{"name":"2012 Asia Pacific Microwave Conference Proceedings","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134409537","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/APMC.2012.6421724
Xuan Anh Nghiem, B. Terres, C. Stampfer, R. Negra
This paper presents the RF characterization and modeling of a back-gated graphene field effect transistor (GFET) embedded in a coplanar waveguide (CPW). The electromagnetic model (EM) of the graphene structure includes both channel and metal/graphene contact resistances as well as all involved parasitic capacitances. The S-parameters of the resulting structures have been measured at room temperature in the frequency range from 10 MHz to 67 GHz for back-gate voltages up to 37 V. Measurements show a roughly back-gate independent contact resistance (~ 900 Ωμm) and a highly rise in channel resistance from 20 Ω to 2.34 kΩ when increasing the back-gate voltage from 0 V to 37 V (Dirac point). Moreover, the associated capacitance decreases from 4.1 fF to 0.7 fF for the same voltage range. The simulation results of the electromagnetic model from the CPW together with the graphene structure are in reasonable well agreement with our measurements.
{"title":"RF model of a back-gated graphene field effect transistor","authors":"Xuan Anh Nghiem, B. Terres, C. Stampfer, R. Negra","doi":"10.1109/APMC.2012.6421724","DOIUrl":"https://doi.org/10.1109/APMC.2012.6421724","url":null,"abstract":"This paper presents the RF characterization and modeling of a back-gated graphene field effect transistor (GFET) embedded in a coplanar waveguide (CPW). The electromagnetic model (EM) of the graphene structure includes both channel and metal/graphene contact resistances as well as all involved parasitic capacitances. The S-parameters of the resulting structures have been measured at room temperature in the frequency range from 10 MHz to 67 GHz for back-gate voltages up to 37 V. Measurements show a roughly back-gate independent contact resistance (~ 900 Ωμm) and a highly rise in channel resistance from 20 Ω to 2.34 kΩ when increasing the back-gate voltage from 0 V to 37 V (Dirac point). Moreover, the associated capacitance decreases from 4.1 fF to 0.7 fF for the same voltage range. The simulation results of the electromagnetic model from the CPW together with the graphene structure are in reasonable well agreement with our measurements.","PeriodicalId":359125,"journal":{"name":"2012 Asia Pacific Microwave Conference Proceedings","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131806467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-12-01DOI: 10.1109/APMC.2012.6421642
Hyunwook Hwang, S. Yang, C. Seo
In this paper, high-efficiency power amplifier is implemented using adaptive bias control circuit for the wireless power transmission (WPT). The high efficiency power amplifier uses the Class-E amplifier structure because the efficiency of the WPT system is strongly affected by the efficiency of power amplifier. The adaptive bias control circuits consist of the directional coupler, power detector and operation amplifier. And the high gain two-stage amplifier using the drive amplifier is performed for the low input stage of power amplifier. The proposed power amplifier using the adaptive bias control circuit can have high efficiency at lower power level.
{"title":"High gain and high PAE power amplifier by employing adaptive bias control circuit for resonant WPT","authors":"Hyunwook Hwang, S. Yang, C. Seo","doi":"10.1109/APMC.2012.6421642","DOIUrl":"https://doi.org/10.1109/APMC.2012.6421642","url":null,"abstract":"In this paper, high-efficiency power amplifier is implemented using adaptive bias control circuit for the wireless power transmission (WPT). The high efficiency power amplifier uses the Class-E amplifier structure because the efficiency of the WPT system is strongly affected by the efficiency of power amplifier. The adaptive bias control circuits consist of the directional coupler, power detector and operation amplifier. And the high gain two-stage amplifier using the drive amplifier is performed for the low input stage of power amplifier. The proposed power amplifier using the adaptive bias control circuit can have high efficiency at lower power level.","PeriodicalId":359125,"journal":{"name":"2012 Asia Pacific Microwave Conference Proceedings","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130837296","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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