The air gap effect on a microstrip-coupled cylindrical dielectric resonator antenna

The effect of the air gap between a cylindrical dielectric resonator antenn a and a microstrip line on the resonant frequency, directivity unloaded e-f actor, and impedance bandwidth are studied(lied The antenna structure ir nu merically simulated with a software package based on the finite-element met hod. Appropriate correction factors are obtained, enabling an antenna engin eer to incorporate the air-gap effect into the design of a microstrip-coupl ed cylindrical dielectric resonator antenna. The correction factors provide Good agreement with the measured results in resonant frequency): unloaded Q-factor, and impedance bandwidth, but less accurate prediction in directiv ity for the specified range of parameters (C) 1999 John WiIey & Sons, Inc.