Network modeling of electromagnetically coupled and active microstrip patch antennas

The advent of sophisticated printed circuit techniques in recent years has spawned several novel circuit and antenna configurations in the microwave frequency range. One such advance has been the microstrip patch antenna which is formed by a metallic patch on a dielectric substrate backed by a ground plane.; In most of the current microwave design practice, circuit and antenna functions are designed separately on single layer substrates and then connected together in the system. Use of two layer substrates for microstrip patch antennas offers increased flexibility in the design, enhancement in performance and opens up the possibility of accommodating active circuitry on the lower substrate.; The research presented in this thesis is aimed at developing design techniques for integrated microstrip circuit-antenna components. The work reported here is in two parts, the major component of it being the development of a network model for analysis and design of a two layer electromagnetically coupled (EMC) patch antenna. The technique used is known as the Multiport Network Modeling (MNM) approach which, in essence, transforms an electromagnetic boundary-value problem into a network problem. Results obtained from MNM are compared with experimental results as well as those obtained by full-wave numerical methods. Parametric studies of a canonical configuration are presented and a design methodology is proposed.; The second part of the research involves integration of active devices with patches to form active patch antennas. A design methodology using MNM to study configurations using the Gunn diode-patch integration is suggested. The use of varactors in tuning these patch antennas is also investigated. Results from simulation studies and experiments are presented.