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In this paper we study the mathematical modelling of a domestic microwave oven with incorporated metallic bars. These bars act like antennas. They are powered by the microwave energy that excites the oven and transmit the energy to the surface of the lossy load (see figure 1). The calculation of the field inside the cavity and of the external characteristics of the cavity as seen by the source guide...
Advancements in microstrip technologies have made possible the development of many miniature multilayered integrated devices, for various antenna and microstrip circuitry applications. The use of a coupling slot (aperture) in these devices is a recent method utilized for coupling electromagnetic energy from one substrate layer to another. This technique generally involves the use of a rectangular...
A Moment Method analysis of a typical circular waveguide polarizer module is described in this paper. The method uses complete sets of entire domain basis and testing functions which provide a high accuracy in the predicted complex scattered fields. Precision design of polarizers can be achieved using this algorithm. Predicted results for a design example are presented.
Marine MSAT requires an antenna array that functions in the 1525MHz to 1660.5MHz frequency band to be placed on sea going vessels. The gain of the overall array should be 14.1dBiC minimum. The implementation chosen is a right-hand circularly polarized microstrip array of four elements.
With the current trend in communications towards extremely high frequencies and minimized system dimensions microstrip patch antennas have the potential to replace reflector antennas as the radiator of choice in certain applications due to their small size, ease of integration, and conformability. However, at millimeter-wave frequencies, significant microstrip transmission line loss occurs. This loss...
This paper presents a coupling of two different methods for electromagnetic scattering problems, the 3D MMP (Multiple MultiPole) code, an implementation of the Generalized Multipole Technique (GMT) and the finite element (FE) method. The coupling is performed by iterative methods. The procedure is illustrated with the solution of benchmark problem for scattering from a three-dimensional lossy dielectric...
Complex propagation characteristics of composite nonradiative dielectric waveguides (NRD) are presented. Dielectric and ohmic losses are considered in this hybrid mode analysis based on the frequency-domain transmission-line matrix approach. Numerical results of mode dispersion characteristics indicate that a class of complex modes in both lossless and lossy cases may be supported in the composite...
This paper presents a new type of microstrip bandpass filter. It is realized in a double-layer configuration, as shown in fig. 1. This design makes use of the vertical dimension to achieve a size reduction over conventional microstrip parallel coupled bandpass filters [1]. These conventional filters have significant overall widths because the widths depend on the number of coupling sections. Also,...
In this presentation a detailed discussion on the measurement of microwave permittivity of dielectric slabs and surface resistivity of thin films are given. A new needle-type coaxial probe with improved performance is also described and evaluated.
A six-port junction is used to perform demodulation of PSK signals directly at RF frequencies. The proposed direct phase demodulator is capable of demodulating various digital modulations such as BPSK, QPSK, etc. The hardware imperfections are readily eliminated by software. Due to the absence of the frequency conversion stages the receiver becomes very simple. Measurements have been performed at...
The translational formula for vector spherical harmonics [1-5] is derived in a very simple and straightforward manner using only a few well known results in the irreducible spherical tensor theory [13-15] and recursion relations of spherical Bessel and Hankel functions.
This paper outlines the development of a new type of digital adaptive-array algorithm for interference cancellation. It is fast in the sense that it requires only order-of-N computations per iteration and converges in a substantially fixed number of iterations (proportional to N) regardless of the signal scenario or geometry of the N-element array. The need for such algorithms arises in dynamic signal...
A generic antenna model which simulates various MLS antenna configurations is described. The performance of the user specified antenna is analyzed using the MLS type parameters such as Effective Radiated Power (ERP), Mean Angle Error (MAE), Filtered Raw Angle (FRA), Control Motion Noise (CMN) and Path Following Error (PFE). Other parameters such as beamwidth, beamshape, dynamic sidelobe level and...
A cellular phone is a portable radio that radiates 0.6 watt from an antenna located very close to the operator's head. Concern has been expressed as to whether a cellular phone is capable of inducing damaging field strengths inside the user's head. This paper reviews the application of electromagnetic modelling techniques using the finite-difference time-domain(FDTD) method to this problem. The construction...
Rick Cassell has 19 years experience working with MLS. He has extensive experience in analyzing MLS integrity and continuity of service. He has worked for the last ten years as an advisor to the U.S. representative on the International Civil Aviation Organization All Weather Operations Panel. He has a Bachelor's Degree in Electrical Engineering from Villanova University.
This paper gives a brief introduction and literature survey, then an overview of propagation research work conducted up to the end of 1993 by affiliates of the CITR Broadband Indoor Wireless Communications Project. Included is a summary of reported results concerning rms delay spread and propagation loss on non-fading (static) indoor channels at radio frequencies between 20 GHz and 60 GHz. The final...
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%.
With increasing application of millimeter wave integrated circuits (mm-ICs) in radiometry, radar, astronomy, and communications, more accurate design data for various waveguide structures are becoming necessary. The majority of the millimeter-wave integrated circuits is based on the printed transmission lines such as suspended microstrip lines [1], fin lines [2] and non-radiating dielectric (NRD)...
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