Triple‐band compact circularly polarised stacked microstrip antenna over reactive impedance meta‐surface for GPS applications

Abstract

In this study, a compact, triple‐band, circularly polarised stacked microstrip antenna is proposed over the artificial eta‐surface called reactive impedance surface (RIS) for enhancing antenna radiation efficiency for GPS applications. The proposed design utilises the concept of combining multi‐stacked patches with RIS as imaginary‐impedance metamaterial‐ground‐plane for selective frequency reduction of lower bands with improvement in antenna radiation properties for multi‐band applications. The circularly polarised (CP) radiation with compact antenna size is achieved for triple‐band GPS frequencies of L1 (1.575 GHz), L2 (1.227 GHz) and L5 (1.176 GHz) by placing three stacked patches with two different pairs of symmetric slits, four different sized symmetric cross‐shaped slots and truncated corners over RIS. As RIS meta‐surface reduces the wave penetration through the lossy substrate beneath it, the proposed stacked patch antenna over RIS demonstrates enhanced forward gain with suppressed back radiation. The measured results for antenna prototype are (1.168–1.185 GHz): L5 band, (1.2–1.245 GHz): L2 band and (1.51–1.59 GHz): L1 band for 10 dB return loss bandwidth with good CP radiation. Forward (boresight) right‐handed CP gain of 2.88 dBic (L5 band), 3.25 dBic (L2 band) and 5.53 dBic (L1 band) is observed for compact antenna overall volume of 0.32λo × 0.32λo × 0.024λo at 1.2 GHz.

Design of a Compact Cp Antenna With Enhanced Bandwidth Using a Novel Hexagonal Ring Based Reactive Impedance Substrate

“…It is observed that our RIS structure provides maximum bandwidth in return loss and axial ratio compared to [15][16][17][18][19]. Gain of the proposed antenna is comparable to [17,18] while co-cross pol isolation is slightly better than [16,19]. The RIS thickness of the proposed structure is also comparable to [15,17,18].…”

“…However, the improvement in axial ratio bandwidth as well as impedance bandwidth was obtained at the increase of either lateral size [6] or vertical size [7,8]. Nowadays, electromagnetic metamaterial [9,10] and metasurface [11][12][13][14][15][16][17][18] have been intensely studied to counter the above two issues, i.e., miniaturization and bandwidth enhancement of CP antenna. In spite of the improvement in bandwidth both radiation efficiency and gain of the antenna are degraded in [9] while use of complementary split ring resonator (CSRR) structure has produced narrow return loss and axial ratio bandwidth in [10].…”

“…The problem featured in [8] in terms of compactness can be alleviated by introducing square RIS below the slotted patch antenna [17]. Compared to square patch RIS, Jerusalem cross RIS provides more gain and better impedance matching for the CP antenna [18]. Recently, a CP antenna has been miniaturized with high gain but low impedance bandwidth using fractal-based reactive impedance substrate [19].…”

“…An analytical approach along with simulation has been presented to describe the reflection phase characteristics of the RIS. The hexagonal ring element has a lower level of metallization than square and circular elements [11][12][13][14][15] and contributes to lower resistive losses [18]. In addition to low losses, hexagonal ring RIS has also produced lower reactive surface impedance than square based RIS.…”

Polarization and Radiation Pattern Reconfigurability of a Planar Monopole-Fed Loop Antenna for GPS Application

“…The device signal cannot pass through dense material such as stone, concrete, metal, dirt, or thick trees. On certain locations, obstructed by tall buildings and with sparse coverage, the signal reception of up to 90% can be poor or even lost [9]. Furthermore, the position of the GPS antenna mounting is crucial for performance of the GPS receiver.…”