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The benefit of hyperthermia as an adjuvant treatment to brachytherapy in the treatment of breast cancer and other accessible tumours has been widely documented [1]. Results obtained by a variety of researchers have been very consistent. A recent review paper shows an improvement in complete response rates from 37% for radiation alone to 63% for combined radiation and hyperthermia treatment [2]. The...
In recent years, the range of applications for microstrip antennas has been expanding rapidly and so has the complexity of the antenna configuration. Multilayer printed-circuit antennas have been gaining much attention because they can improve antenna characteristics such as bandwidth and side lobe levels. They are also well-suited for multi-frequency operation as well as dual polarization. Frequency...
In this paper, the analysis of slot-coupled microstrip structures is considered. Typical methods applied to the analysis of this class of problem include: analytic techniques such as modal-field analysis [1], cavity models [2]; and the numerical solution of integral-equation formulations [3]. The Transmission Line Matrix (TLM) method is a general numerical technique for obtaining an approximate solution...
The stacked quad EMC super patch with probe feeding was first proposed in [1] and a number of design results for personal communication terminals were provided in [2]. It has wide bandwidth of stacked microstrip antennas and higher gain due to the radiation of subarray. On the other hand, aperture coupling[3] can reduce the interaction between the antenna and feeding network, and the feed can be placed...
A multi-layer patch antenna that is fed by a gap discontinuity within a microstrip feed line is investigated. The feed line is located on the lower layer of the structure, while a rectangular patch is centred above the gap discontinuity on the upper layer. The structure is analyzed by the moment method in the spatial domain and employs a matched load simulation technique. Comparison with experimental...
The next generation of SAR antennas are expected to operate in dual linear polarization. This implies that more demanding specification for cross-polarization isolation is required. In current SAR antenna designs the acceptable cross-pol level (within the 3dB beamwidth of the copolar patterns) was −20dB. For the new generation of SAR antennas the cross-pol level is expected to be better than −25dB...
The analysis of microstrip structures has received a great deal of attention from many different researchers [1],[2]. Of particular interest is the Mixed Potential Integral Equation (MPIE) formulation as presented by Mosig and Gardiol [1]. This method exploits the continuity equation to develop an integral equation in terms of both surface current and surface charge densities. The solution scheme...
Much attention has been paid to circular polarized self-diplexing antennas[1]-[3], for mobile satellite communications. Among them, the two-layer configuration[2]-[3] seems to be suitable for reduction of the array size. Most self-diplexing antennas described earlier are either direct microstrip line-fed or probe-fed. For the application to higher frequencies, such as Ka-band or millimeter wave band,...
A new ring coupled triangular microstrip antenna has been investigated experimentally. The measured bandwidth of the proposed antenna is obtained 309 MHz (7.14% at fo = 4.33 GHz), which is 4 times the band width of the corresponding triangular patch antenna. The gain of the antenna is 3 dB and cross polar level is better than 12 dB within the impedance bandwidth of 7%.
This paper investigates the RCS of two aircraft in the HF frequency range, for a plane wave incident on the nose of the aircraft with the electric field oriented vertically. The “generic aircraft” is a simplified aircraft geometry which demonstrates the basic features of aircraft RCS in the HF band. Good agreement is obtained between the measured RCS, that obtained by wire-grid modelling, and that...
This paper concerns the calculation and measurement of the RCS of a trihedral corner reflector. The calculations are performed using the moment method and the Uniform Theory of Diffraction (UTD). The measurements are performed at 2–18 GHz in an anechoic chamber. Comparison between the measurements and the calculations shows a good agreement. The results show that as the angle of incidence is increased,...
Synthetic time domain processing can be used to produce range-only RCS images of stationary targets in the laboratory environment. If the target is rotated in angle, two dimensional images can also be constructed. However, to image a moving target, the synthetic time-domain processing must use pulsed signals. The DREO I/J band RCS measurement radar has recently been modified so it can collect coherent...
The MMP modeling of different scattering structures is discussed. It is shown, that highly accurate near and farfield simulations are possible, not only for simple academic structures such as spheres or cubes, but also for a multiturn helical wire of finite thickness and an absorbing ferrite cylindre placed on a cable. Although the amount of calculation increases when edges or tips are present, rather...
This paper will present codes whose function is to pre- and post-process information used by the Numerical Electromagnetic Code Basic Scattering code and the Richmond Thin Wire code. The processor uses the MATLAB environment for the fundamental graphical functions. The Basic Scattering Code uses the principles of ray optics as well as the geometrical theory of diffraction. The Richmond code uses a...
The synthetic aperture radar (SAR) antenna on-board the Canadian remote sensing satellite, RADARSAT, is a large deployable planar array (1.5m × 15m) [1], [2]. It provides a set of selectable pseudo-trapezoidal elevation beam shapes (see figure 1–1) which afford flexible coverage within a 500 km wide accessibility region, which runs parallel to, and to the side of, the orbital plane of the spacecraft...
Radarsat is a Canadian Synthetic Aperture Radar (SAR) system which will provide continually updated and global sea ice, geological, land and forest resource management data [1]. The first satellite will be launched in 1995.
The RADARSAT mission utilizes a Synthetic Aperture Radar (SAR) system to produce images representing terrain radiometric backscatter levels. The SAR system consists of Space and Ground Segments. The Space Segment is a polar orbiting satellite at 800 km nominal altitude carrying a C-band (5.3 GHz) radar sensor. The Ground Segment provides the SAR image data processing facility, as well as the associated...
The RADARSAT Synthetic Aperture Radar (SAR) antenna is a large (1.5m × 15m) slotted waveguide planar array operating at 5.3 GHz. The antenna comprises 32 slotted waveguide rows, and is mechanically divided into 4 panels to enable stowage during launch. Each waveguide row is fed by a 1-to-8 azimuth power dividing network (APDN). The 32 rows of the APDN are excited across the 1.5m dimension by the elevation...
In MIC's and printed antennas the dielectric substrates always have finite extent. Rigorous analysis of the truncation effects requires the solution of an integral equation with MoM. This is usually numerically intense especially for 3-D structures. In this paper the truncation effects are incorporated directly in an approximate Green's function. The Characteristic Green's Function (CGF) technique...
Coaxial lines are most widely used in driving microwave devices and antennas and in extracting outputs from them. In practice, both two processes involve a number of coaxial junctions which provide transfer characteristics dependent on the bandwidth of the microwave signal. Where transient characteristics of an antenna or any other device are to be investigated, the major prerequisite is to have a...
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