Triple-Resonance Wideband Sector Patch Antenna Under 1.25-Wavelength

Based on the multi-mode resonance theory, this paper proposes an advanced wideband sector patch antenna with an enhanced tilted angle and range of circularly polarized (CP) beams. The design of the sector patch antenna is inspired by a 1.25-wavelength prototype magnetic dipole. The outer arc, being 1.25-wavelength in length, enables the effective excitation of three odd-order resonance modes. In the design, the triple-resonance wideband characteristic is obtained by integrating the second odd-order mode with the first and third modes, perturbed through the introduction of two slits and a shorting pin. Furthermore, since the
E
-amplitudes contributed by the three modes are equal at a specific angle, the introduced pin is also employed to achieve a 90° phase shift, enabling CP radiation around the resonant frequency of the second mode. As an experimental validation, the sector patch antenna with a flared angle of 180° and a low profile of 0.069-wavelength is fabricated and measured. The results demonstrate an impedance bandwidth of 45.9%, a 3 dB axial ratio (AR) bandwidth of 12.1%, and an enhanced tilted angle and range, with the maximum CP beam tilted angle reaching 42° and a tilted range of 34°. In comparison to its counterpart, the proposed antenna exhibits a simple configuration and an enhanced gain up to 8.3 dBi in the tilted direction (θ = 15° and φ = 0°).