||In recent years, the development of wireless communication systems has grown rapidly, and the requirement of high data rate is also soaring significantly. To meet the requirements of high speed data rate transmission, the IEEE defined the standard of 802.11ad for new wireless communication technology. It uses the 60-GHz band to provide wireless communication. However, the range of millimeter wave propagating in air is short. In order to overcome this disadvantage, high gain antennas are required. In this thesis, we propose the patch antenna array which has the property of high gain and wideband operating from 57 to 66 GHz.|
Traditional patch antenna has the advantages of high radiation efficiency and low profile. The high radiation efficiency has superiority for high propagating attenuation in the 60-GHz band. But, the bandwidth of patch antenna is only less than 5%. Regarding this, we apply aperture coupled feed and the bandwidth is extended to more than 8%. However, the traditional aperture coupled feed structure has an air layer and the air layer can only be implemented by ion implantation and razer process, both of these two processes cost a lot. To avoid expensive fabrication cost, we adopt stacked structure to replace the original design (with the air layer) and maintain the performances.
The request of bandwidth is about 15% of the band from 57 to 66 GHz. Considering that we need to achieve wideband and high gain performances simultaneously, we utilize the stronger coupling between neighbor elements of series-array, to enhance bandwidth to 20%. In the meantime, the gain performance is also improved to 8.2dBi on 1x2 series-array from 6dBi on a single antenna. Moreover, comparing with parallel-array, series-array feeding network is much simpler and easy to design. The gain enhancement is not as good as parallel-array feeding network design when we increase antenna elements to series-array feeding network design directly. Therefore, we combine both series and parallel feeding network, and design a 4x4 aperture coupled feed path array with the properties of easy fabrication, wideband and gain performance reaches 15dBi.