Summary
International Symposium on Antennas and Propagation
2008
Session Number:4C31
Session:
Number:4C31-5
A Probe-Fed Patch Antenna with a Step-Shaped Ground Plane for WLAN Access Point
Fa-Shian Chang, Saou-Wen Su, Jui-Hung Chou, Chia-Hung Lu, Hong-Twu Chen,
pp.-
Publication Date:2008/10/27
Online ISSN:2188-5079
Summary:
Many patch antennas utilizing thick air substrates have been developed and studied to achieve impedance bandwidth exceeding 10% defined by 2:1 VSWR or 5% by 1.5:1 VSWR for broadband operation [1-6]. Among these researches, a short probe pin of the probe feed is mostly employed in conjunction with various matching mechanism. That is because for patch antenna with such thick air substrate, using a long probe pin can cause large inductance, which makes it very difficult to well match the antenna to impedance bandwidth within VSWR of 2. In addition to the use of a short probe pin, the matching mechanism in these studies also demonstrates some modification to the structure of the antenna feed. These designs include the use of a bevel-feed transition [1], a cylinder-feed transition [2], a T-shaped probe feed [3], an L-shaped probe feed [4], an edge-fed patch with an L-shaped ground [5], a ridge-shaped ground [6], and so forth. In this paper, we introduce a new design of a probe-fed patch antenna capable of broadband operation. The antenna is backed by a step-shaped ground plane and can be fed by a long probe pin at one of the patch radiating edges. Simply by tuning the probe-pin length, good impedance matching over frequency band with 1.5:1-VSWR bandwidth of about 6% can be obtained. Several design prototypes have been built, and a design example aimed for operation in the 2.4 GHz (2400-2484 MHz) WLAN band has been implemented too. The proposed antenna is designed for access-point applications in the WLAN environment. Details of the antenna design are described, and experiment results are discussed.