Unidirectional Antenna Using Two-Probe Excited Circular Ring Above Square Reflector for Polarization Diversity With High Isolation

Abstract

Abstract-This paper presents a circular ring antenna fed by two perpendicular probes, both of which are placed above the square reflector. The antenna is employed to radiate unidirectional beam for polarization diversity reception. A linear isolator is added to improve the isolation between the two probes. The antenna is proposed for the point-to-point communication of Wireless Local Area Network (WLAN) system according to the IEEE 802.11a standard in which the allocated frequency band ranges from 5.150 GHz to 5.825 GHz. The proposed antenna is compact and suitable for mass production. Without the dielectric material, the antenna is free of dielectric loss and capable of high power handling. The prototype antenna was fabricated and measured to verify the theoretical predictions. At the center frequency, the unidirectional pattern with the measured half-power beamwidths in two principal planes of 65 and 75 degrees is achieved. The front-to-back ratio is 31 dB, and the antenna gain is 7.42 dBi. The |S 11 | and |S 21 | are respectively −23.09 dB and −33.99 dB; the obtained bandwidth is 23.64%. Based on the aforementioned characteristics, the antenna is a potential candidate for polarization diversity of WLAN applications.

Multiband Handset Antenna Analysis Including Lte Band Mimo Service

“…Even though the separation between them is as far as possible within the available space of a mobile handset, the electric distance of this separation is not enough to obtain good isolation using a spatial diversity technique in the lower frequency band. In general, when two linearly polarized antennas are located orthogonal to each other, they can provide polarization diversity by reducing the mutual coupling, so that high isolation and low ECC can be achieved between them [25,26]. However, this technique with vertical and horizontal polarizations does not work very well for handset antennas in the lower frequency such as the LTE 13 (746 ∼ 787 MHz) band because their ground size are usually much smaller than their wavelength (λ 0 = 429 mm).…”

Design of Dual Circularly Polarized Antenna With High Isolation for Rfid Application

“…Recently, The polarization diversity in one antenna body has been proposed and widely used for location and communication applications, such as satellite navigation, 2G/3G mobile and WLAN system [16][17][18][19][20][21][22][23][24]. In this paper, a novel dual circularly-polarized antenna design is adopted for RFID reader.…”

A Broadband Technique for a Decoupling Network in a Compact Antenna Array in a Mimo System

“…When two linearly polarized antennas are located orthogonally to each other, they can reduce the mutual coupling and provide polarization diversity [15,16]. However, they require a large antenna space and ground.…”