The finite-difference time-domain (FDTD) method is a widely used numerical technique for computer-aided design (CAD) of printed antennas and arrays. This technique can accurately predict performance characteristics of complex microstrip antennas, including the effects of parasitic elements and aperture-coupled feeds. In the case of arrays, mutual coupling effects between closely packed elements can also be modeled. This article will examine the advantages and limitations of the FDTD method for CAD of microstrip arrays. Calculated results are compared with experiment for a 3-patch coplanar parasitic patch array.

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Frequency selective surfaces (FSS's) are often used in spaceborne applications of reflector antennas due to their ability to allow multiple feeds to utilize the same reflector dish. The problems inherent in evaluating the FSS separately from the reflector system are discussed. A method of integrating the FSS effects into the reflector system analysis is presented. An example is given for the proposed Advanced Tracking and Delay Relay Satellite System (ATDRSS) singleaccess trihand reflector antenna.

The performance of a four‐frequency‐band (S/X/Ku/Ka) frequency‐selective surface (FSS) with double‐ring elements is evaluated both for a flat panel development and for a curved subreflector in a dual reflector antenna. Good agreement is observed between the measured and computed data for the flat panel FSS. To accurately predict the FSS effects on a dual reflector antenna's radiation pattern, we take into account the FSS subreflector's transmitted/reflected field variation as functions of the polarization and incident angles with respect to the local coordinates. An FSS transmission/reflection coefficient table is computed for TE and TM polarizations at various incident angles based on the planar FSS model. Next, the hybrid geometric optics (GO) and physical optics (PO) technique is implemented with linear interpolation of the FSS table to efficiencly determine the FSS effects in a dual reflector antenna. © 1993 John Wiley & sons, Inc.