Using characteristic mode theory to estimate air-substrate microstrip patch antenna input impedance

The input impedance of an antenna is a crucial parameter when designing antenna systems. Although this impedance may be transformed into a desired value by using a matching network, a better solution when possible is to design the antenna itself to present the desired input impedance. For certain types of antennas, this design process is well-researched and fairly straightforward; rectangular microstrip patch antennas are one example. For many other cases, full-wave parametric simulations are the only viable alternative. Here, an alternate analysis technique for these situations is developed to estimate the input impedance of a particular class of antennas.