Pub Date : 2001-09-09DOI: 10.1109/HFPSC.2001.962165
L. Y. Tio, L. Davis
The behaviour of a magnetised semiconductor can be characterised by a permittivity tensor, which combines the ohmic and displacement currents. The frequency dependence of the permittivity tensor elements is described. A semiconductor that is magnetised transverse to the direction of propagation such that the microwave electric field is perpendicular to applied static magnetic field (i.e. a TM mode) is described by an effective permittivity, /spl epsi//sub eff/. The variation of /spl epsi//sub eff/ of indium antimonide (/spl epsi//sub r/=17.7) as a function of frequency up to the terahertz region is described. The reflection and transmission coefficients for oblique incidence on a simple dielectric and semiconductor interface have been derived and it can be shown that a reflectionless condition is achievable only at normal incidence. The frequency dependence of the complex reflection coefficient for normal incidence is presented and discussed.
{"title":"Gyroelectric properties of indium antimonide at terahertz frequencies","authors":"L. Y. Tio, L. Davis","doi":"10.1109/HFPSC.2001.962165","DOIUrl":"https://doi.org/10.1109/HFPSC.2001.962165","url":null,"abstract":"The behaviour of a magnetised semiconductor can be characterised by a permittivity tensor, which combines the ohmic and displacement currents. The frequency dependence of the permittivity tensor elements is described. A semiconductor that is magnetised transverse to the direction of propagation such that the microwave electric field is perpendicular to applied static magnetic field (i.e. a TM mode) is described by an effective permittivity, /spl epsi//sub eff/. The variation of /spl epsi//sub eff/ of indium antimonide (/spl epsi//sub r/=17.7) as a function of frequency up to the terahertz region is described. The reflection and transmission coefficients for oblique incidence on a simple dielectric and semiconductor interface have been derived and it can be shown that a reflectionless condition is achievable only at normal incidence. The frequency dependence of the complex reflection coefficient for normal incidence is presented and discussed.","PeriodicalId":129428,"journal":{"name":"6th IEEE High Frequency Postgraduate Colloquium (Cat. No.01TH8574)","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125309439","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 : 2001-09-09DOI: 10.1109/HFPSC.2001.962167
T. Brabetz, V. Fusco
In this paper, a GaAs millimetre-wave detector for positive bias is presented. The circuit uses a 0.20 /spl mu/m GM Schottky diode and achieves a state of the art sensitivity of approximately 1100 mV/mW under optimum conditions in the 65.5 GHz range. The bias is applied through a voltage divider, allowing for signals with very low frequencies to be detected. The detector has been integrated together with a patch antenna onto a single chip of 1.0/spl times/1.5 mm/sup 2/, exhibiting similar sensitivities to the stand alone version. The integration resulted in a very small, mass producible detector circuit for broadband broadcasting, millimetre-wave propagation measurements, and motion detection applications.
{"title":"A millimetre-wave detector for short range applications","authors":"T. Brabetz, V. Fusco","doi":"10.1109/HFPSC.2001.962167","DOIUrl":"https://doi.org/10.1109/HFPSC.2001.962167","url":null,"abstract":"In this paper, a GaAs millimetre-wave detector for positive bias is presented. The circuit uses a 0.20 /spl mu/m GM Schottky diode and achieves a state of the art sensitivity of approximately 1100 mV/mW under optimum conditions in the 65.5 GHz range. The bias is applied through a voltage divider, allowing for signals with very low frequencies to be detected. The detector has been integrated together with a patch antenna onto a single chip of 1.0/spl times/1.5 mm/sup 2/, exhibiting similar sensitivities to the stand alone version. The integration resulted in a very small, mass producible detector circuit for broadband broadcasting, millimetre-wave propagation measurements, and motion detection applications.","PeriodicalId":129428,"journal":{"name":"6th IEEE High Frequency Postgraduate Colloquium (Cat. No.01TH8574)","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129124613","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 : 2001-09-09DOI: 10.1109/HFPSC.2001.962175
T.F.J. Girvan, V. Fusco, A. Roberts
This paper describes the development of a mathematical algorithm to determine the volumetric array factor of a nonplanar conformal array. It shows the vector translation required to collimate the beam of each element to a common point. Following this, an illustration shows the mathematical rotations required to represent each element with respect to a common set of axes. A set of equations describes these rotations in Cartesian mathematical form. These are incorporated into a MATLAB/sup (R)/ program to calculate the array factor. The program was tested and validated by comparing its output against that of the commercial method of moments wire antenna simulation tool NEC-WIN PRO/sup (R)/ for a number of array variants. The results were found to be consistent.
{"title":"A method for calculating the radiation pattern of a non-planar conformal array","authors":"T.F.J. Girvan, V. Fusco, A. Roberts","doi":"10.1109/HFPSC.2001.962175","DOIUrl":"https://doi.org/10.1109/HFPSC.2001.962175","url":null,"abstract":"This paper describes the development of a mathematical algorithm to determine the volumetric array factor of a nonplanar conformal array. It shows the vector translation required to collimate the beam of each element to a common point. Following this, an illustration shows the mathematical rotations required to represent each element with respect to a common set of axes. A set of equations describes these rotations in Cartesian mathematical form. These are incorporated into a MATLAB/sup (R)/ program to calculate the array factor. The program was tested and validated by comparing its output against that of the commercial method of moments wire antenna simulation tool NEC-WIN PRO/sup (R)/ for a number of array variants. The results were found to be consistent.","PeriodicalId":129428,"journal":{"name":"6th IEEE High Frequency Postgraduate Colloquium (Cat. No.01TH8574)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125493886","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 : 2001-09-09DOI: 10.1109/HFPSC.2001.962188
C. Ng, M. Chongcheawchamnan, I. Robertson
The design and performance of a monolithic microwave I-Q type vector modulator operating at 26 GHz is presented. The MMIC chip which measures 1.75 mm /spl times/ 2.1 mm, employs direct carrier modulation to reduce hardware complexity and cost. The static constellation was obtained with swept bias voltage control, with this, modulation of 16-quadrature amplitude modulation (QAM) is demonstrated. Baseband input levels were applied at 2.5 MSample/s, by an arbitrary waveform generator to demonstrate a 10 Mbits/s data rate transmitter operating at 26 GHz.
介绍了一种工作频率为26 GHz的单片微波I-Q型矢量调制器的设计和性能。MMIC芯片尺寸为1.75 mm /spl × 2.1 mm，采用直接载波调制，降低了硬件复杂性和成本。在扫频偏置电压控制下获得了静态星座，并对16正交调幅(QAM)调制进行了论证。基带输入电平为2.5 MSample/s，通过任意波形发生器来演示在26 GHz下工作的10 Mbits/s数据速率发射机。
{"title":"A balanced vector modulator for LMDS applications","authors":"C. Ng, M. Chongcheawchamnan, I. Robertson","doi":"10.1109/HFPSC.2001.962188","DOIUrl":"https://doi.org/10.1109/HFPSC.2001.962188","url":null,"abstract":"The design and performance of a monolithic microwave I-Q type vector modulator operating at 26 GHz is presented. The MMIC chip which measures 1.75 mm /spl times/ 2.1 mm, employs direct carrier modulation to reduce hardware complexity and cost. The static constellation was obtained with swept bias voltage control, with this, modulation of 16-quadrature amplitude modulation (QAM) is demonstrated. Baseband input levels were applied at 2.5 MSample/s, by an arbitrary waveform generator to demonstrate a 10 Mbits/s data rate transmitter operating at 26 GHz.","PeriodicalId":129428,"journal":{"name":"6th IEEE High Frequency Postgraduate Colloquium (Cat. No.01TH8574)","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132272235","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 : 2001-09-09DOI: 10.1109/HFPSC.2001.962157
G. Watkins
Software defined radio (SDR) is often heralded as the future of mobile communications with some aspects expected within the fourth generation of European standards. An SDR suitable for commercial narrow- and broad-band applications will typically cover the frequency spectrum between 400 MHz and 6 GHz. This range encompasses all of the (worldwide) existing and emerging standards alongside likely future developments. In order to facilitate such a radio, in the absence of efficient flexible filters, a super-octave-band front-end is needed. The receiver will be subject to all the signals within this band, both wanted and interfering. It is likely that the stronger interfering signals will cause intermodulation products (IMP) within the nonperfect low noise amplifier (LNA). These IMPs can interfere with a wanted signal and, potentially, make it undetectable. This paper reports the results of a radio trial, indicating the strength, frequency and geographical location of potentially interfering signals around the Bristol area. Results are presented for typical urban, suburban, and rural environments and hotspots. The results presented in this paper give an indication of the practical dynamic range requirements of an SDR receiver operating in the frequency spectrum between 400 MHz and 6 GHz.
{"title":"Potential interfering signals in software defined radio","authors":"G. Watkins","doi":"10.1109/HFPSC.2001.962157","DOIUrl":"https://doi.org/10.1109/HFPSC.2001.962157","url":null,"abstract":"Software defined radio (SDR) is often heralded as the future of mobile communications with some aspects expected within the fourth generation of European standards. An SDR suitable for commercial narrow- and broad-band applications will typically cover the frequency spectrum between 400 MHz and 6 GHz. This range encompasses all of the (worldwide) existing and emerging standards alongside likely future developments. In order to facilitate such a radio, in the absence of efficient flexible filters, a super-octave-band front-end is needed. The receiver will be subject to all the signals within this band, both wanted and interfering. It is likely that the stronger interfering signals will cause intermodulation products (IMP) within the nonperfect low noise amplifier (LNA). These IMPs can interfere with a wanted signal and, potentially, make it undetectable. This paper reports the results of a radio trial, indicating the strength, frequency and geographical location of potentially interfering signals around the Bristol area. Results are presented for typical urban, suburban, and rural environments and hotspots. The results presented in this paper give an indication of the practical dynamic range requirements of an SDR receiver operating in the frequency spectrum between 400 MHz and 6 GHz.","PeriodicalId":129428,"journal":{"name":"6th IEEE High Frequency Postgraduate Colloquium (Cat. No.01TH8574)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127431218","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 : 2001-09-09DOI: 10.1109/HFPSC.2001.962148
R. Gaddi, J. Plá, P. Tasker
Compression and harmonic generation mechanisms coupled to the non-linear output drift-region capacitance of Silicon LDMOS FET transistors are thoroughly investigated. Large-signal time-domain analysis is performed on the device operated as a class AB amplifier. Observations confirm significant real power being shifted from the fundamental to the even order harmonics by the capacitive element acting effectively as a varactor diode multiplier.
{"title":"Harmonic power generation from the non-linear output capacitance of silicon LDMOS devices","authors":"R. Gaddi, J. Plá, P. Tasker","doi":"10.1109/HFPSC.2001.962148","DOIUrl":"https://doi.org/10.1109/HFPSC.2001.962148","url":null,"abstract":"Compression and harmonic generation mechanisms coupled to the non-linear output drift-region capacitance of Silicon LDMOS FET transistors are thoroughly investigated. Large-signal time-domain analysis is performed on the device operated as a class AB amplifier. Observations confirm significant real power being shifted from the fundamental to the even order harmonics by the capacitive element acting effectively as a varactor diode multiplier.","PeriodicalId":129428,"journal":{"name":"6th IEEE High Frequency Postgraduate Colloquium (Cat. No.01TH8574)","volume":"345 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115892987","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 : 2001-09-09DOI: 10.1109/HFPSC.2001.962179
W. Ismail, P. Gardner
A patch antenna integrated with two Low Noise Amplifiers (LNA) is implemented to act as an Image Reject Mixer (IRM). The low noise active antenna system transforms a received radio frequency signal into two signals, which are out-of phase to each other. The image signals can be cancelled by the IRM. The antenna, LNA's, mixers and local oscillator (LO) are integrated into a single Active Integrated Antenna (AIA) module. An external IF 90/spl deg/ hybrid coupler is required in the IRM. The advantages of the LNA active antenna mixer system are low noise, image signal rejection, low cost and simple circuitry of front-end, and improved receiver sensitivity.
{"title":"Low noise integrated active antenna as image reject mixer (IRM)","authors":"W. Ismail, P. Gardner","doi":"10.1109/HFPSC.2001.962179","DOIUrl":"https://doi.org/10.1109/HFPSC.2001.962179","url":null,"abstract":"A patch antenna integrated with two Low Noise Amplifiers (LNA) is implemented to act as an Image Reject Mixer (IRM). The low noise active antenna system transforms a received radio frequency signal into two signals, which are out-of phase to each other. The image signals can be cancelled by the IRM. The antenna, LNA's, mixers and local oscillator (LO) are integrated into a single Active Integrated Antenna (AIA) module. An external IF 90/spl deg/ hybrid coupler is required in the IRM. The advantages of the LNA active antenna mixer system are low noise, image signal rejection, low cost and simple circuitry of front-end, and improved receiver sensitivity.","PeriodicalId":129428,"journal":{"name":"6th IEEE High Frequency Postgraduate Colloquium (Cat. No.01TH8574)","volume":"217 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122926994","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 : 2001-09-09DOI: 10.1109/HFPSC.2001.962163
J.B. Mills, C. Stevens, D. Edwards
A strategy leading to development of tunable microwave planar devices is described. The characterisation of composite material systems is outlined and initial results are reported. Material systems based on SU-8 epoxy resist offer a viable route to ferrite loaded elements suitable for planar device fabrication.
{"title":"Composite materials for planar frequency agile microwave devices","authors":"J.B. Mills, C. Stevens, D. Edwards","doi":"10.1109/HFPSC.2001.962163","DOIUrl":"https://doi.org/10.1109/HFPSC.2001.962163","url":null,"abstract":"A strategy leading to development of tunable microwave planar devices is described. The characterisation of composite material systems is outlined and initial results are reported. Material systems based on SU-8 epoxy resist offer a viable route to ferrite loaded elements suitable for planar device fabrication.","PeriodicalId":129428,"journal":{"name":"6th IEEE High Frequency Postgraduate Colloquium (Cat. No.01TH8574)","volume":"31 5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125524766","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 : 2001-09-09DOI: 10.1109/HFPSC.2001.962151
T. Wilson, D. K. Paul
Effective feedforward linearization of a power amplifier can be achieved without compromising performance, using an auxiliary amplifier of lower power than the main amplifier overcoming the inefficiency of the classic feedforward configuration, which employs two amplifiers of the same power rating. Reduction of the power rating of the auxiliary amplifier will lead to improved system efficiency. It is shown that the operating output power level and consequential intermodulation distortion level of the main amplifier are critical in determining the minimum saturation power level of the required auxiliary amplifier. Results of theoretical calculations and CAD simulations for the required minimum saturation power level of the auxiliary amplifier are presented and indicate close agreement.
{"title":"Feedforward linearizer with reduced output auxiliary amplifier","authors":"T. Wilson, D. K. Paul","doi":"10.1109/HFPSC.2001.962151","DOIUrl":"https://doi.org/10.1109/HFPSC.2001.962151","url":null,"abstract":"Effective feedforward linearization of a power amplifier can be achieved without compromising performance, using an auxiliary amplifier of lower power than the main amplifier overcoming the inefficiency of the classic feedforward configuration, which employs two amplifiers of the same power rating. Reduction of the power rating of the auxiliary amplifier will lead to improved system efficiency. It is shown that the operating output power level and consequential intermodulation distortion level of the main amplifier are critical in determining the minimum saturation power level of the required auxiliary amplifier. Results of theoretical calculations and CAD simulations for the required minimum saturation power level of the auxiliary amplifier are presented and indicate close agreement.","PeriodicalId":129428,"journal":{"name":"6th IEEE High Frequency Postgraduate Colloquium (Cat. No.01TH8574)","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127572507","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 : 2001-09-09DOI: 10.1109/HFPSC.2001.962154
H. Scott, V. Fusco
Beam steering is defined as the ability to electronically steer the beam maximum of an antenna electric field pattern to some predefined point in space. Leaky wave antennas can be used for such a purpose but include inherent problems such as large size, difficulty in impedance matching and a large number of sidelobes in the resultant electric field pattern. This paper concentrates on a method for mimicking the operation of a typical leaky wave antenna array by the simple integration of a phase shifter into the array structure. Up to 12/spl deg/ beam steer is demonstrated using the integrated array whose structure is short and compact compared to the typical leaky wave arrays. The bias voltage of the phase shifter is used to control the impedance match of the array reducing the VSWR to below 1.5 where the 12/spl deg/ beam steer is experienced. The phase shift between the elements of the array, used to provide beam steering, is provided by scanning the frequency through a range of frequencies from 1.17 GHz to 1.23 GHz. This range is greatly reduced from typical leaky wave antenna arrays because the phase shifter also acts to provide an additional phase shift between the elements. The resultant radiation patterns also show improved characteristics as the number of sidelobes has been decreased.
{"title":"Antenna array beam-steering by the integration of a series phase shifter","authors":"H. Scott, V. Fusco","doi":"10.1109/HFPSC.2001.962154","DOIUrl":"https://doi.org/10.1109/HFPSC.2001.962154","url":null,"abstract":"Beam steering is defined as the ability to electronically steer the beam maximum of an antenna electric field pattern to some predefined point in space. Leaky wave antennas can be used for such a purpose but include inherent problems such as large size, difficulty in impedance matching and a large number of sidelobes in the resultant electric field pattern. This paper concentrates on a method for mimicking the operation of a typical leaky wave antenna array by the simple integration of a phase shifter into the array structure. Up to 12/spl deg/ beam steer is demonstrated using the integrated array whose structure is short and compact compared to the typical leaky wave arrays. The bias voltage of the phase shifter is used to control the impedance match of the array reducing the VSWR to below 1.5 where the 12/spl deg/ beam steer is experienced. The phase shift between the elements of the array, used to provide beam steering, is provided by scanning the frequency through a range of frequencies from 1.17 GHz to 1.23 GHz. This range is greatly reduced from typical leaky wave antenna arrays because the phase shifter also acts to provide an additional phase shift between the elements. The resultant radiation patterns also show improved characteristics as the number of sidelobes has been decreased.","PeriodicalId":129428,"journal":{"name":"6th IEEE High Frequency Postgraduate Colloquium (Cat. No.01TH8574)","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134434726","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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