Extremely low-profile wideband dual-polarized microstrip antenna for micro-base-station applications

Abstract

A wideband dual‐polarized microstrip antenna is presented. By designing the coplanar parasitic patches and modified feed probes, antenna profile is decreased significantly. Shorted pins are used and 34 dB isolation between input ports is then achieved. A phase difference feed network is introduced to suppress higher‐order modes and reduce the cross polarization to −27 dB. To verify the design, a prototype of the antenna is fabricated and experimentally studied. Measured results show that 30.3% operating bandwidth (VSWR < 1.5) and good dual linear polarization characteristics with a profile height as low as 0.08λ are achieved. Due to the very compact configuration, the proposed antenna is suitable for micro‐base‐station applications.

A low‐profile wideband dual‐polarization patch antenna with antisymmetric feeding network

“…It is noted that the proposed antenna has the highest gain except for the antenna in Reference , but this work has a lower profile than the antenna in Reference . Besides, the antennas in References , and need additional power dividers or external feeding networks for providing anti‐phase excitation signal, which increases the complicate the structure, manufacturing cost and the loss from the power dividers, and the antennas in References and have a lower profile than this work, but the gain fluctuation in Reference is larger than this work, and the antenna in Reference has narrower impedance bandwidth and lower gain than this proposed antenna.…”

A wideband patch antenna with a pair of antisymmetric balun as differentially fed network

“…The antennas have only about 18% impedance bandwidth, while the proposed antenna has more than 30% impedance bandwidth. The differentially‐fed antennas has a wideband and low cross‐polarization, but they need external circuitry for differentially‐fed network. For example, the size of the antenna section is only 0.32 λ 0 × 0.18 λ 0 × 0.16 λ 0 ( λ 0 is the free‐space wavelength at center frequency) in Ref.…”

“…Although the detailed dimensions of the antennas in Refs. and are not given, they need additional feeding network on the ground plane, which complicates the structure and increases the manufacturing cost. The proposed antenna does not need external feed networks, so the size of the antenna is only 0.43 λ 0 × 0.43 λ 0 × 0.14 λ 0 , which can decrease the antenna cost in mass production.…”

“…Compared with the antenna in Ref. , the proposed antenna in this article does not need extra power dividers, which can reduce the total size of the antenna system and the power loss in the power divider.…”

“…However, the bandwidth of the patch antenna with differentially feeding is only about 18%, which is unable to meet the requirements of modern wireless communication systems. Later, the impedance bandwidth over 30% can be achieved …”