Low‐profile circularly polarized microstrip patch antenna with pattern diversity

Abstract

This letter presents a two‐port circularly polarized pattern diversity microstrip patch antenna. The antenna is designed on a single layer with a low profile (0.021λ0, where λ0 is the free‐space wavelength at the central frequency). The broadside pattern and conical pattern of the antenna can be obtained by respectively exciting the fundamental mode of the inner circular patch and the high‐order mode of the entire circular patch. With four pairs of silts on the patch, the antenna achieves circular polarization for both broadside and conical patterns. A prototype of it is fabricated and measured. The measured overlapped bandwidth of 10‐dB return‐loss and 3‐dB axial ratio for both modes are 1.3% (1.569‐1.580 GHz) and 0.6% (1.565‐1.575 GHz), respectively. Moreover, the measured peak gain values are 6.4 and 3.7 dBi for broadside and conical modes, respectively. The satisfactory isolation (|S21| < −22 dB) is also achieved between the two feeding ports in the common impedance matching bands.

Compact in‐band pattern diversity antenna for wireless applications

“…In Gulur et al 15 and Rahul et al, 16 a millimeter wave antenna and a circularly polarized antenna were proposed for in‐band pattern diversity application, but different radiators are need for different operating modes. With one radiator, broadside and conical radiation patterns were achieved by the antenna with size of 120 × 100 × 6 mm 3 , 17 the antenna with size of 200 × 200 × 20.626 mm 3 , 18 the antenna with size of 160 × 160 × 18 mm 3 , 19 and the antenna with size of 160 × 160 × 1 mm 3 20 …”

“…In this article, a novel omni‐directional/uni‐directional pattern diversity antenna is proposed. Different radiation patterns are achieved by exciting different areas of the single radiating patch, leading to a compact antenna size (36 × 36 × 3.4 mm 3 ), which is much smaller than that of the antennas 17–20 . Owing to the symmetry of the antenna structure, the mutual coupling between the two operating modes can be canceled out at the feeding network, resulting in a high inter‐channel isolation over 30 dB.…”

“…With one radiator, broadside and conical radiation patterns were achieved by the antenna with size of 120 Â 100 Â 6 mm 3 , 17 the antenna with size of 200 Â 200 Â 20.626 mm 3 , 18 the antenna with size of 160 Â 160 Â 18 mm 3 , 19 and the antenna with size of 160 Â 160 Â 1 mm 3 . 20 In this article, a novel omni-directional/uni-directional pattern diversity antenna is proposed. Different radiation patterns are achieved by exciting different areas of the single radiating patch, leading to a compact antenna size (36 Â 36 Â 3.4 mm 3 ), which is much smaller than that of the antennas.…”

“…Different radiation patterns are achieved by exciting different areas of the single radiating patch, leading to a compact antenna size (36 Â 36 Â 3.4 mm 3 ), which is much smaller than that of the antennas. [17][18][19][20] Owing to the symmetry of the antenna structure, the mutual coupling between the two operating modes can be canceled out at the feeding network, resulting in a high inter-channel isolation over 30 dB. A quarter wavelength microstrip resonator integrated in the feeding networks and a parasitic patch placed above the derived patch are used to enhance the impedance bandwidths of the omni-directional and uni-directional radiation pattern modes, respectively.…”

A low‐profile circularly polarized dielectric patch antenna with bandwidth expansion

“…In order to improve the quality of signal transmission and solve the polarization mismatch problem, circularly polarized (CP) antennas have received much attention in recent years 1‐3 . Among them, the CP microstrip patch (MP) antenna has been widely researched due to its advantages such as low profile, light weight, and high gain 4‐9 . However, as the low‐frequency spectrum gradually saturated, the operating frequency of RF front end rises to a higher band.…”