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Volume 151
Issue 2
IEE Proceedings - Microwaves, Antennas and Propagation
Volume 151, Issue 2, April 2004
Volumes & issues:
Volume 151, Issue 2
April 2004
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- Author(s): L.-C. Tsai ; H.-M. Chen ; C.-W. Hsue
- Source: IEE Proceedings - Microwaves, Antennas and Propagation, Volume 151, Issue 2, p. 97 –103
- DOI: 10.1049/ip-map:20040177
- Type: Article
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p.
97
–103
(7)
A new configuration consisting of parallel coupled lines (PCLs) and nonuniform transmission lines (NTLs) is employed to study lowpass and bandstop filters. In particular, each section of both PCLs and NTLs has the same electrical length. As a result, the transfer functions of such networks are formulated in the Z-domain. An optimisation algorithm is used to tune the characteristic impedances of coupled-serial-shunted lines so that the transfer functions of signal lines are close to the system functions of ideal prototype filters. A Butterworth bandstop filter and two equal-ripple lowpass filters are realised in the form of microstrip lines and their frequency responses are measured to validate this novel method. - Author(s): K.W. Eccleston and O. Kyaw
- Source: IEE Proceedings - Microwaves, Antennas and Propagation, Volume 151, Issue 2, p. 104 –108
- DOI: 10.1049/ip-map:20040174
- Type: Article
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p.
104
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The analysis of, and derivation of design equations for, a class-B balanced single-ended dual-fed distributed amplifier is presented. This approach allows efficient combining of FET output power without multi-way power combiners, has a good port match, and is easy to design as the gate and drain transmission lines are uniform. The design method ensures that all FETs are optimally used and the efficiency is comparable to that of a conventional single-transistor class-B power amplifier using the same FET type. The design method was applied to a class-B four-FET balanced single-ended dual-fed distributed amplifier designed to operate at 1.8 GHz. Large-signal measurements revealed 8% downward shift of the centre frequency. The measured output power and drain efficiency was consistent with the simulations. The efficiency of the amplifier was comparable to a conventional single-transistor class-B power amplifier using the same type of FET. - Author(s): V. Volski and G.A.E. Vandenbosch
- Source: IEE Proceedings - Microwaves, Antennas and Propagation, Volume 151, Issue 2, p. 109 –114
- DOI: 10.1049/ip-map:20040192
- Type: Article
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p.
109
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(6)
A microstrip antenna located on a finite ground plane has been analysed. The calculation is split into several steps. In the first step, the microstrip antenna on an infinite ground plane is analysed using the moment method. In the next step, the radiation pattern is calculated using ray tracing techniques. The fields in the layered structure are expanded into a finite number of expansion waves. The expansion waves propagate up to the edges of the finite ground plane, where they diffract. Diffraction coefficients for these waves are calculated using a formulation based on the aperture integral equation. The experimental results are in good agreement with the proposed model. - Author(s): M.H. Chiou and K.Y.J. Hsu
- Source: IEE Proceedings - Microwaves, Antennas and Propagation, Volume 151, Issue 2, p. 115 –120
- DOI: 10.1049/ip-map:20040169
- Type: Article
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p.
115
–120
(6)
A new wideband modelling technique is presented, to exactly model the time-domain (TD) responses of microwave spiral inductors. This new method is suitable for modelling the spiral inductors used in switching-type microwave circuits, such as LC tank voltage-controlled oscillators (VCOs), or filters. The technique was developed based on applying an ultra-short impulse signal (30 ps) to the device. Furthermore, the layer-peeling technique (LPT) and hybrid equivalent circuits were used in the modelling process. Experiments were conducted to reveal the feasibility of the technique. Results show that the generated wideband models can be used to describe the TD responses of spiral inductors with a timescale down to picosecond order. - Author(s): J. Verhaevert ; E. Van Lil ; A. Van de Capelle
- Source: IEE Proceedings - Microwaves, Antennas and Propagation, Volume 151, Issue 2, p. 121 –126
- DOI: 10.1049/ip-map:20040173
- Type: Article
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p.
121
–126
(6)
The design and realisation of a dodecahedral antenna is investigated. The three-dimensional design with pentagonally shaped faces is described. The simulation program NEC2 (numerical electromagnetics code, version 2) is used to simulate the proposed design. This dodecahedral antenna configuration is optimised for all pertinent parameters, according to the coupling constraints and the radiation pattern. The coupling values and the radiation pattern are measured and compared with the simulated values. - Author(s): A. Trastoy ; Y. Rahmat–Samii ; F. Ares ; E. Moreno
- Source: IEE Proceedings - Microwaves, Antennas and Propagation, Volume 151, Issue 2, p. 127 –130
- DOI: 10.1049/ip-map:20040175
- Type: Article
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p.
127
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A 19-element linear array was synthesised that can be switched between narrow-beam and broad-beam patterns with stringent sidelobe level and roll-off requirements using only eight-bit phase shifters. The sensitivity of its performance to errors in element position, excitation phase or amplitude was analysed. Results obtained using simulated annealing and a genetic algorithm for optimisation were very similar, and consumed very similar amounts of computer time. - Author(s): Z. Wang ; X. Chen ; C.G. Parini
- Source: IEE Proceedings - Microwaves, Antennas and Propagation, Volume 151, Issue 2, p. 131 –134
- DOI: 10.1049/ip-map:20040362
- Type: Article
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p.
131
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The effects of the whole human body and the ground on the performance of a handset antenna are studied through EM simulation. The complexity of the radiation pattern of a handset antenna is illustrated, and the specific absorption rate (SAR) level inside the head is increased using a more realistic model which includes the partial ground, the whole body and the hand. Four human models of different heights are compared, showing that the changing of model height has an effect on the SAR inside the human body and causes a slight variation of the far-field pattern. However, the different property of the ground plane has a more noticeable effect on the SAR and the far-field patterns. - Author(s): Y. Zhang ; Y.L. Mo ; J.Q. Li ; X.L. Zhou
- Source: IEE Proceedings - Microwaves, Antennas and Propagation, Volume 151, Issue 2, p. 135 –142
- DOI: 10.1049/ip-map:20040165
- Type: Article
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p.
135
–142
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The vane-loaded helical slow-wave structure is widely used in high power, broadband travelling wave tubes (TWTs). Taking the radial thickness of the helix into account, the finite size vane model is suggested for vane-loaded helical slow-wave structures (SWS). The expressions of the dispersion equations, interaction impedance and attenuation constant of this model are derived. Two vane-loaded helical slow-wave structures of the travelling wave tube (TWT) are calculated by the derived equations. The calculated results are compared with the results of measurement and the calculated results of the infinite number of vanes model (INV) that also considered the radial thickness of the helix. The influence on dispersion characteristics is analysed for the thickness of the helix and different centre angles of the vanes. It is interesting to find that the centre angle (2θ) of the vanes has a fixed value when the phase velocity is a minimum. - Author(s): E. Nishiyama ; M. Aikawa ; S. Egashira
- Source: IEE Proceedings - Microwaves, Antennas and Propagation, Volume 151, Issue 2, p. 143 –148
- DOI: 10.1049/ip-map:20040171
- Type: Article
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p.
143
–148
(6)
The behaviour mechanism of the stacked antenna is synthetically clarified for the first time by investigating the results calculated using the FDTD method. The stacked microstrip antenna has particular characteristics, such as a high gain or a wide bandwidth. When the size of the parasitic patch, is nearly equal to the fed patch and the distance between the fed patch and the parasitic patch is approximately 0.1 wavelength, the bandwidth is increased. When that distance is approximately half a wavelength, the gain enhancement is obtained. The wide bandwidth and the gain enhancement are considered synthetically by the detailed investigation of calculated results including the near-field distributions. It is shown that the wide bandwidth and the gain enhancement are caused by a two-frequency resonance and leaky resonant cavity formation, respectively. The calculated input impedance and radiation patterns agree well with the experimental values. - Author(s): C.-H. Tseng and T.-H. Chu
- Source: IEE Proceedings - Microwaves, Antennas and Propagation, Volume 151, Issue 2, p. 149 –155
- DOI: 10.1049/ip-map:20040179
- Type: Article
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p.
149
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The principle, measurement system, calibration and experimental results of microwave diversity imaging of conducting objects in a multisource illumination arrangement are presented. Theoretical analysis is developed under multiple plane wave illumination and physical optics approximation. The measurement system and calibration procedure are implemented based on plane wave spectrum analysis. Reconstructed images of four different types of conducting objects, including continuous shape and discrete line objects, measured in the frequency range 7.5–12.5 GHz, are shown in good agreement with the scattering object geometries. The experimental results demonstrate that the developed microwave imaging system is an effective approach to yield microwave images of scattering objects with a wide aspect angle. - Author(s): R. Lech and J. Mazur
- Source: IEE Proceedings - Microwaves, Antennas and Propagation, Volume 151, Issue 2, p. 156 –160
- DOI: 10.1049/ip-map:20040166
- Type: Article
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p.
156
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A waveguide filter employing several conducting cylindrical posts that have a bow-tie shape is synthesised and investigated. The boundary problem of the bow-tie post that is used as a filter section is analysed using an iterative scattering procedure and the orthogonal expansion method. The procedure allows the fast calculation of the modal scattering matrix of the circuit. The shape of the investigated structure, its dimensions, rotation and location in the waveguide junction introduce additional degrees of freedom which can be used to tune the filter so as to obtain the required frequency response characteristic. The rotation of the posts enables the resonant frequency to be slightly changed, which helps to correct any inaccuracies created during fabrication. A good agreement is obtained between the results of this method and those obtained from FDTD simulations and measurements. - Author(s): M.S. Al Salameh and A.H. Jarandal
- Source: IEE Proceedings - Microwaves, Antennas and Propagation, Volume 151, Issue 2, p. 161 –166
- DOI: 10.1049/ip-map:20040149
- Type: Article
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p.
161
–166
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Mobile communications for low bit rate applications via midearth orbit (MEO) satellites are considered. Owing to multipath interference, fading of the received signal appears in low bit rate applications. The received signal levels, at the mobile in the presence of buildings, are calculated using the uniform theory of diffraction (UTD) for horizontal and vertical polarisations. Buildings are considered in both residential and moderate urban environments.For easy reference, explicit mathematical representations with illustrations of all significant ray contributions are given. Furthermore, the signal levels data, extracted from the electromagnetics computations, are used to evaluate communication system performance in terms of bit error rate and depolarisation of the received signal. Moreover, computed results are in agreement with actual measured data. - Author(s): R. Dehghani and S.M. Atarodi
- Source: IEE Proceedings - Microwaves, Antennas and Propagation, Volume 151, Issue 2, p. 167 –172
- DOI: 10.1049/ip-map:20040164
- Type: Article
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p.
167
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An analytic method to predict the oscillation amplitude and supply current values of a differential CMOS oscillator. A simplified model to predict the phase noise performance for this type of oscillator is developed. Using this method, it becomes possible to design an optimised oscillator in terms of a minimum phase noise and low power consumption. The validity of the method has been verified by designing a LC CMOS oscillator using 0.25 μm CMOS technology. The predictions are in good agreement with simulation results over a wide range of the supply voltage. - Author(s): D. Delaune ; T. Tanaka ; T. Onishi ; J.T. Sri Sumantyo ; K. Ito
- Source: IEE Proceedings - Microwaves, Antennas and Propagation, Volume 151, Issue 2, p. 173 –179
- DOI: 10.1049/ip-map:20040148
- Type: Article
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p.
173
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The Japan Aerospace Exploration Agency (JAXA) plans to launch a geostationary satellite called Engineering Test Satellite-VIII (ETS-VIII) in 2004. In the paper, the feasibility of reaching a relatively high value of gain at low elevation angle by use of a simple left-handed circularly polarised four-element stacked patch array antenna for mobile satellite communications in the S-band frequency aiming at ETS-VIII applications is discussed. The characteristics of this antenna are confirmed by two numerical methods (the method of moments and the finite element method) and by measurements. Furthermore, the influence of the finite size of the ground plane was analysed using of the finite element method. Both numerical analyses and measurements are presented. In addition, the operation of beam-switching is experimentally confirmed. It is revealed that, by properly feeding the patches constituting the antenna, for an elevation El=48° (θ=42°) in Tokyo, four beams are created in the conical-cut direction at azimuth Az=6°, 96°, 190°, and 276°. The gain reached more than 6.5 dBic on the whole azimuthal range, with an axial ratio less than 3 dB.
Z-domain formulations of equal-length coupled-serial-shunted lines and their applications to filters
Analysis and design of class-B dual fed distributed power amplifiers
Modelling of a microstrip antenna on a finite ground plane using the expansion wave concept and the aperture integral equation formulation
A new wideband modelling technique for spiral inductors
Three-dimensional monopole antenna for direction of arrival determination
Two-pattern linear array antenna: synthesis and analysis of tolerance
Effects of the ground and the human body on the performance of a handset antenna
Modelling of finite size vane-loaded helical slow-wave structures
Stacked microstrip antenna for wideband and high gain
Principle and results of microwave diversity imaging of conducting objects using multisource illumination
Tunable waveguide filter with bow-tie metallic posts
Impact of buildings on the performance of MEO satellite mobile communication systems for low bit rate applications
Design of an optimised 2.5 GHz CMOS differential LC oscillator
Simple satellite-tracking stacked patch array antenna for mobile communications experiments aiming at ETS-VIII applications
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