Dual-Resonant Circular Sector Patch Antenna with Backfire Radiation Enhancement

As revealed within the paper, a circular patch antenna with circumference of 2.0-wavelength can exhibit backfire enhancement performance. At first, a group of approximate formulas on the basis of multi-resonant theory are given to identify the flared angle, radii and the usable resonant modes. Then, the method of pin-loading is used at the zero of the magnetic current to perturb the fundamental resonant mode to realize the characteristic of dual-resonant wideband. At last, a prototype antenna on a 3-mm-thick (0.06-wavelength) air substrate is manufactured, measured and verified. It is confirmed that the resonant modes TM
1/2, 1
and TM
3/2, 1
can be simultaneously excited, perturbed and applyed for radiation. As validated, the proposed antenna can exhibit backfire radiation gain of -0.5 dBi over a wide bandwidth of 26.2%.