High-Gain, Low-Cost Polarization-Reconfigurable Antenna With Switchable Single and Dual Beams by Digital Phase-Coding Method

A high-gain polarization-reconfigurable antenna array with switchable single and dual beams is proposed in this article. To realize the polarization-reconfigurable and beam-switching functions, a compact digital phase-coding antenna (DPCA) element is first presented. By manipulating the operating probes and branches, right-/left-handed circular polarization (RHCP/LHCP) with 2-bit phase code and 0°-/90°-linear polarization (0°-LP/90°-LP) with 1-bit phase code are realized. Moreover, the realized gain is enhanced by introducing a novel annular-slotted parasitic patch. Then, beam-switching principle is explored and confirmed with a four-element array. As a result, both the single and dual beams are switchable by controlling the phase code of each element. The element and array are fabricated and verified, respectively. The array achieves 28 reconfigurable states, i.e., the single beam for CP states and the dual beam for CP/LP states are steered within ±30° and ±51°, respectively. Besides, the proposed array achieves high realized gains of 11.27 dBi (single beam)/9.03 dBi (dual beam) and efficiency up to 85.4% at the central operating frequency. The measured results indicate that the proposed DPCA has low cost, compact size, high gain, and excellent pattern/polarization control capacity, providing new insights into the realization of satellite antennas and smart antennas.