A Single-Feed Dual-Band Dual-Beam Filtering Patch Antenna With Concurrent CP and LP Properties

A single-feed dual-band dual-beam filtering patch antenna with both circular polarization (CP) and linear polarization (LP) properties is proposed in this letter. Dual bow-tie-shaped patches are used for concurrently achieving dual-beam and CP radiation in the lower passband. By employing L-shaped metal strips and a folded T-shaped stepped impedance feedline (FTSIF), the filtering response is introduced, simultaneously giving rise to the upper passband with LP operation. Additionally, through loading a T-shaped resonator, a deep radiation null (RN) is yielded between the two passbands. Consequently, dual-beam filtering responses with CP in the lower and LP in the upper passbands are, respectively, realized. For validation, a prototype is fabricated and tested. Two measured passbands operate at 5.30 GHz to 5.69 GHz and 6.11 GHz to 6.29 GHz, showing good dual-beam CP and LP radiation, respectively.