Antenna Design with EBG Superstrate for Gain and Bandwidth Enhancement
Date Issued
2009
Date
2009
Author(s)
Chen, Yi-Chia
Abstract
This thesis presents a novel EBG-based high gain PCB antenna. The antenna consists of a conventional printed patch antenna for the bottom layer and a superstrate with printed periodic strips for the top layer. With proper design on the periodic strips of the top layer known as partial reflective surface (PRS), the region between the two layers may form a resonant cavity that can be air or dielectric loaded. Under the optimized design of the PRS and cavity height, the coherent resonant waves may be radiated from the PRS with an in-phase sense leading to an enhanced gain at the zenith direction. e illustrate the proposed antenna design on cost-effective FR4 PCBs with operational frequency around 5GHz for IEEE 802.11a WLAN applications. The resultant antenna dimensions in this thesis have the area ranges from 70mm2 to 100mm2 and the total height from 2mm to 3.5mm. Two design examples are presented for the cavity filled by air and dielectric, respectively. The first design employs the air cavity and performs promising results including the 10-dB return loss bandwidth of 20% and the peak gain of 11.5 dBi with 3-dB and 1-dB gain bandwidth about 25% and 12%, respectively. Compared to the traditional 2x2 patch array of the same area (75 mm2), the proposed antenna improves the equivalent aperture efficiency from 46 to 70%. The other design using the dielectric loaded cavity may further reduce the antenna height to l0/30. The final antenna area is 70 mm2 with measured performances including the 10-dB return loss bandwidth of 12%, the peak gain of 9.9 dBi, and the aperture efficiency of 55%. The simulation and measurement results show very good agreement in this thesis.
Subjects
EBG Antenna
PCB Antenna
High Gain Antenna
Type
thesis
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