ABSTRACT
Microstrip antennas are one of the most widely used types of antennas in the microwave frequency range, and they are often used in the millimeter-wave frequency range as well [1-3]. (Below approximately 1GHz, the size of a microstrip antenna is usually too large to be practical, and other types of antennas such as wire antennas dominate.) Also called patch antennas, microstrip patch antennas consist of a metallic patch of metal that is on top of a grounded dielectric substrate of thickness h, with relative permittivity and permeability "r and r r various shapes, with rectangular and circular being the most common, as shown in Fig. 9.1. Most of the discussion in this section will be limited to the rectangular patch, although the basic principles are the same for the circular patch. (Many of the CAD formulas presented will apply approximately for the circular patch if the circular patch is modeled as a square
below.
