Numerical analysis of honeycomb antennas with an electromagnetic coupling feed system

The first- and zeroth-mode radiation characteristics of a honeycomb antenna are analysed using the method of moments. The honeycomb antenna is fed by an unbalanced feed system, where an inverted L-wire is electromagnetically coupled to the antenna. The number of radiation cells is chosen to be N_x=2 in the x-direction and N _y=13 in the y-direction. The first-mode radiation shows that, as the interior angle a increases, the half-power beam widths (HPBWs) in the two principal planes become wider. The maximum gain is obtained at α=180°. The zeroth-mode radiation shows that, as α increases, the HPBW in the H-plane decreases, while the HPBW in the E-plane increases. A maximum gain of approximately 19 dB is obtained at α=80°. Evaluation of the area factor, defined by the concept similar to the aperture efficiency, reveals that the zeroth-mode radiation has a larger value than the first-mode radiation