A MIXED SPECTRUM ANALYSIS OF A MICROSTRIP DISK RESONATOR

The radiation properties of a microstrip disk resonator excited by a c ylindrical line probe is investigated analytically. A mixed spectrum e igenwave expansion is employed to describe the electromagnetic fields below and above the microstrip resonator. A voltage gap generator mode l is used to take into account the excitation of the radiation structu re. An integral equation is obtained on the semi-infinite cylinder enc ircling the microstrip disk with the unknown term being the vertical c omponent of the aperture electric field. The integral equation is solv ed by applying an iterative procedure, where the magnetic-walls soluti on is employed as the initial approximation. Then, the input impedance of the microstrip disk is determined by computing the total current a t the feeding point. Radiation patterns are also computed and presente d.