A small single fed broadband circularly polarized slot antenna

Abstract

In this research, we present a simple single fed small broadband circularly polarized (CP) antenna. The proposed structure has the advantage of simultaneously obtaining broadband ARBW and IMBW in a small size (0.64λ × 0.62λ × 0.01λ), where λ is the free‐space wavelength at the center frequency. The measured S11 BW is 100% (2.15‐6.44 GHz), which is completely overlapped by the measured ARBW of 108.7% (2.09‐7.07 GHz), which are wider than most published papers. The antenna consists of an off‐center microstrip feed line, an inverted rectangular bracket‐shape (IRBS) parasitic strip, and a modified ground plane. The modified ground plane has three linked slots and a protruded L‐shaped stub (LSS). The IRBS parasitic strip and the feed line are on one side of the substrate, whereas the ground plane is on the other side. The IRBS and LSS are overlaid up and down. The novelties of the structure are that the design mechanics is simple and clear as follows: (a) The three linked slots make the ground asymmetrical, and the asymmetrical ground makes the broadband IMBW in a small size preliminarily formed. Though the AR is around 8 dB, the fluctuation of AR inside the operation frequency band is little. (b) The off‐center feeding line, IRBS parasitic strip, and the LSS chain together through capacitance coupling, and the current path is formed, then the AR below 3 dB in the whole frequency band is generated. The peak gain and radiation efficiency are of 5.5 dBi and 95%, respectively. The proposed antenna is a good candidate for the application of various wireless communication systems, such as WLAN, WiMAX, and RFID.

Broadband Circular Polarised Printed Antennas for Indoor Wireless Communication Systems: A Comprehensive Review

“…The IBW and ARBW were thus improved. The latest development in broadband CP slot antennas was proposed by Huang and Zhang [18], who used different IBW and ARBW improvement techniques. The proposed design integrates most of the techniques used in previous research as shown in Figure 18.…”

“…Printed antennas are receiving considerable attention with regard to their use in indoor environments because of their compact size, low profile, simple design, uncomplicated design and fabrication and low production cost [ 10 , 16 , 17 , 18 ], in addition to their capabilities of generating CP waves whilst retaining a compact antenna size [ 19 , 20 ] and providing bidirectional radiation patterns, RHCP and LHCP; these properties are essential for antennas which are used in indoor environments [ 21 ]. However, these types of antennas suffer from the difficult trade-off between the achieved IBW and axial ratio bandwidth (ARBW) and their size [ 22 , 23 , 24 , 25 , 26 ].…”

“…The wireless device works at 5.15-5.35 and 5.725-5.825 GHz. Several researchers have focused on the development of a CPW-fed BCPPSA, including its working principle, technical specifications and analysis [100,101].The latest development in broadband CP slot antennas was proposed by Huang and Zhang[18], who used different IBW and ARBW improvement techniques. The proposed design integrates most of the techniques used in previous research as shown in Figure18.…”

Novel square slot circularly polarized antenna with broadband characteristics

“…Several CP slot antennas with various modified slot ground planes are extensively studied recently. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] First, a square-slot ground plane and a modified microstrip-line are printed on both sides of a substrate. Second, by introducing some strips/slots into the square-slot ground plane and modifying the microstrip-line, various CP slot antennas with broadband characteristics are designed.…”

“…Recently, some stirps and slots are also introduced into the ground to generate new CP resonant points to decrease the antenna profile. [13][14][15][16][17][18][19][20] For example, a rectangular slot and an L-shaped strip, 13 L-shaped slots and spiral slots, 14 a vertical stub and inverted L-stubs, 15 and a I-strip and an antipodal Y-strip 16 are etched and inserted into the slot ground for realizing 75.1%, 54.2%, 64.6%, and 41% ARBW, respectively.…”