Design Of Wearable Antenna Applied To The Body Area Network

Body Area Network (BAN), is a network attached to human body, can realize information interconnection between human body and other equipment, and wearable antenna is very important because it is used to send and receive information in BAN. Wearable antenna mainly has two forms: one kind is a hard solid antenna with very small size, another kind is made of flexible material that can be bended on body. Due to the particularity of wearable antenna, the design process to consider the stability and the radiation to human body of the antenna, in order to solve these two problems, an artificial magnetic conductor (AMC) structure with synthetic reflection phase was adopted, and proposed compact AMC structures, which has smaller size and better performance compared to the traditional AMC structure. Several single and double frequency wearable antennas were designed in this article, which worked in industrial, scientific and medical (ISM) open spectrum of BAN:1) A hard button antenna was designed, which work at the double frequency of ISM. The shape of antenna can be disguised as a standard metal button, and it's very hard that can't out of shape easily. But it is stereo and not low profile, and has omnidirectional radiation characteristics, so we designed several flexible wearable antenna with AMC structure, which can realize low profile, and reduce the radiation to human body.2) An flexible single frequency monopole antenna was designed which work at the low frequency of ISM, and load the Mushroom-like AMC structure, which can improve the positive gain of the antenna, and reduce radiation to human body. Its bandwidth is 80 MHz, the positive gain was increased from -2.8 dBi to 8.2 dBi, and the back radiation was significantly reduced,the antenna's height is 2.2 mm, the flat area is 3226.24 mm~2.3) A compact hexagonal AMC structure was proposed to loaded on the bottom of the monopole antenna, narrowing the size of each unit of AMC structure by slit the hexagon copper,and its effective synthetic reflection phase was broaden from 60 MHz to 100 MHz, the antenna with AMC structure high 2.4 mm, and the plane area of it is 1834.09mm~2, the positive gain increased to 6.68 dBi, the radiation to the human body was reduced at the same time.4) A dual-band circular nested monopole antenna was designed, which covers both bands of ISM, and designed a double-frequency hexagon AMC structure. The antenna with AMC structure high 2.6 mm, and the plane area of it is 2123.72mm . The gain of both bands of the antenna were improved by more than 8dB, and the back radiation was significantly reduced.