R. Fralich

Multifunctional aperture coupled stacked antenna

A multifunctional aperture coupled stacked patch antenna that operates at dual-frequency bands is presented. At the lower frequency band, the antenna exhibits a 2:1 voltage standing wave ratio (VSWR) bandwidth of 20%. At the higher frequency band it behaves like a conventional narrowband patch antenna with a 2:1 VSWR bandwidth of 3%. Measured VSWR and far-field radiation patterns as well as numerical predictions are presented. A proper choice of the patch dimensions has been found critical to achieve this multifunctional performance.<<ETX>>

Full-wave analysis of an assortment of printed antenna structures using the FD-TD method

Simple and complex microstrip antennas are analyzed using the FDTD (finite-difference-time-domain) method. The complex antennas that are analyzed consist of broadband and/or dual-band aperture-coupled stacked microstrip antennas. The strengths and the limitations of the FDTD technique for microstrip antenna analysis are demonstrated by comparing the FDTD results with experimental results. It is also shown that the FDTD method is a very useful tool for designing wideband and multiple-band microstrip antennas.<<ETX>>

Experiments with an aperture-coupled, stripline-fed microstrip patch antenna

The authors describe experimental measurements of input impedance and co- and cross-polarized radiation of a stripline-fed, aperture-coupled microstrip patch antenna in different configurations. The measured antenna module is shown. A 50- Omega stripline sandwiched between two 0.125-in-thick layers of RT/duroid 6006 ( epsilon /sub r/=6.0) feeds a square microstrip patch centered over a center-fed rectangular coupling slot. The patch is etched onto a 0.125-in-thick sheet of RT/duroid 5870 ( epsilon /sub r/=2.33). The effect of ground plane size and of shielding the substrate edge is investigated.<<ETX>>

Design study of an integrated array architecture

The design of a circularly polarized, integrated phased array antenna is described. The design is based on a multilayer architecture in which both passive and active components, consisting of antenna elements, feed lines, phase shifters, amplifiers, and power combiners, are integrated. Aperture coupling is used for coupling components between the layers of the antenna. Some of the outstanding issues that must be resolved before this architecture becomes a practical reality are discussed.<<ETX>>

Finite array effects on the patch element pattern, mutual coupling and input impedance

Measured results are provided to demonstrate how patch element performance varies in a small, eight-element array environment as compared with an isolated patch antenna. Element patterns, mutual coupling, and input impedance in the finite array environment were investigated. The measured elemental patterns and input impedances are compared with those for a single, isolated patch element.<<ETX>>

Mutual coupling of two microstrip line-fed patch antennas

The authors present early results of a numerical analysis of a general patch antenna array with coplanar microstrip feed lines. First, the input impedance and resonant frequency of an isolated patch element with microstrip line feed on a lossless substrate are considered, followed by a discussion of the mutual coupling between two identical patch antennas. The impedance matrix and the feed model criteria which are critical in predicting the input impedance and mutual coupling, are also mentioned. A more accurate feed model for the microstrip line-fed patch element is currently being developed based upon experiments using an HP-8510B network analyzer.<<ETX>>