Flat-plate antenna techniques and constraints on performance

Microstrip is the name given to a type of open waveguiding structure that is now commonly used in present-day electronics, not only as a transmission line but for circuit components such as filters, couplers, resonators etc. Readers not completely familiar with the microstrip concept are referred to Chapter 2 for some explanatory details and references. The idea of using microstrip to construct antennas is a much more recent development and an example of a microstrip antenna is given in Fig. 1.1. The antenna assembly is physically very simple and flat which are two of the reasons for the great interest in this new antenna topic. The upper surface of the dielectric substrate supports the printed conducting strip which is suitably con toured while the entire lower surface of the substrate is backed by the conducting ground plate. Sometimes the antennas are referred to as printed antennas because of the manufacturing process.