Differential-Fed Dual-Polarized Filtering Fabry-Perot Antenna With High Isolation

Abstract

In this paper, a dual-polarized filtering Fabry-Perot antenna (FPA) with high-isolation is proposed. It consists of a feed element of differential-fed dual-polarized square patch and a partially reflecting surface (PRS). The patch is capacitively coupled with T-shaped resonators and shorting-vias to obtain broadband characteristic and radiation nulls. The PRS structure is composed of two complementary metasurface layers are selected for achieving a positive reflection phase gradient within the broad frequency range. More interestingly, thanks to the frequency selectivity feature, the PRS significantly enhances the filtering characteristic of the FPA. For verification, a prototype of the proposed antenna operating at the 5.5-GHz center frequency has been fabricated and measured. The prototype with an overall size of ∼2.0λ min × 2.0λ min × 0.49λ min (λ min is the free-space wavelength referring to the lowest operational frequency) result in an impedance bandwidth of 17.1% (5.02 − 5.96 GHz) for 10-dB return loss and a high isolation of ≥ 45 dB. Moreover, the far-field measurements result in a good dual-polarized radiation with the peak gain of 13.0 dBi, cross-polarization level of ≤ -25 dB within the passband, and out-of-band suppression level of ≥ 20 dB.

A High-Gain Filtering Fabry-Perot Antenna With RCS Reduction

“…Nevertheless, it should be emphasized that compared to all other FPAs, our design introduces the filtering characteristics using a very simple CAMS-integrated PRS (one substrate layer with only one type of PRS unit-cell), which is unique among others. As compared to the existing designs with high-gain and filtering features [28], [29], [30], [31], [32], only our FPA achieves RCS reduction.…”

“…Table 1 shows a comparison of the proposed design and the related works, including non-FPA antennas with high gain and filtering performances [11], [12], [13], [14], [15], [16], [17], [28], [29], [30], [31], [32]. It should be noted that this study targets a design with filtering performance, which is often required for narrow band operation so the radiation bandwidth is not a figure of merit in this particular case of comparison.…”

“…For higher gain, the filtering antennas are traditionally arrayed in the previous works, such as [28], [29], [30], and [31], which require complicated feeding networks and design configurations. Recently, a FPA with simple structure has been reported for both filtering and high-gain features [32]. However, this filtering FPA did not yield the scattering reduction.…”

A Novel Dual-Polarized Filtering Antenna for 5G Base Station Applications

“…In [8], a novel filtering antenna was designed by combining T-shaped resonator and PRS (partially reflecting surface). This antenna can cover a wide fractional bandwidth of 17.1% with a high port isolation of 45 dB.…”