A Compact Dual-Band Tripolarized Patch Antenna With Simple Structure and Very High Isolation
Son Xuat Ta, Tran Hien Bui, Khac Kiem Nguyen, Nghia Nguyen‐Trong
Abstract
A compact dual-band tripolarized antenna with simple structure and high isolation operating at 2.45 GHz and 3.5 GHz bands is presented. The design is composed of a slotted patch and a monopolar patch connected together by four vias. The antenna uses a double differential-fed scheme for x-and y-horizontally polarized broadside radiations and a single-ended port at the center for vertically-polarized omnidirectional radiation. The combination of slotted patch, monopolar patch, and vias yields several interesting features, which are exploited in the design to achieve dual-band tripolarized operation. Thank to the differential feed scheme and structural symmetry, the proposed antenna achieves a very high isolation among all ports. For verification, the final design is fabricated and measured. The double differential-fed scheme are realized by using two wideband out-of-phase power dividers, whose operational bandwdith covers both 2.45 and 3.5 GHz bands. The antenna with profile of 0.09λ2.45-GHz yields a measured 10-dB return loss bandwidth of 2.43 – 2.49 GHz and 3.23 – 3.66 GHz and isolation of ≥ 35 dB among all ports. Tripolarized radiation is verified with far-field measurement, showing highly symmetrical pattern and low cross-polarization in all three operational modes. The proposed design is a good candidate for dual-band communication systems which require polarization and pattern diversity antennas.