High gain broadside mode operation of a cylindrical dielectric resonator antenna using simple slot excitation

In this work, the authors report the operation of a cylindrical dielectric resonator antenna (CDRA) in the high gain HEM13 delta mode, for the first time. This mode, excited with a standard microstrip slot, radiates in the broadside direction with gain in the range of 8-10 dBi. It is shown that through feed optimization, the HEM13 delta mode can be excited dominantly by suppressing the fundamental HEM11 delta mode of the CDRA. Detailed simulation studies show that the HEM13 delta mode is supported by cylindrical dielectric resonators with an aspect ratio (radius to height ratio or a/d) >1, and it resonates at a frequency approximately 2.2 times that of the fundamental HEM11 delta mode. The above features of the HEM13 delta mode CDRA can be used as approximate design rules. For a CDRA with dielectric constant e(r) = 24, diameter 2a = 19.43 mm, and height d = 7.3 mm (a/d = 1.3), the HEM13 delta mode is excited at 6.125 GHz with a peak gain of 10.14 dBi in simulation. Corresponding values from prototype measurement are 5.981 GHz and 9.62 dBi, respectively for the resonant frequency and the gain, verifying the simulation.