Imbedded spiral antenna for endoscope

This paper analyses the characteristics of dual spiral antenna with varying length. This antenna is operated in the lower band of the radio frequency range, since human body absorbs the microwave signals. Here the concept of multilayer substrate is used in order to reduce the size of the antenna. The existing system has several limitations. Firstly, most capsules are powered by an internal battery cell that restricts capsule miniaturization. Secondly, current systems are incapable of maintaining a continuous communication link due to the random orientations of the capsule. Therefore an efficient communication link between the in-body capsule and the external receiver unit is important for the development and applicability of the Wireless Capsule Endoscopy (WCE). These limitations are overcome by this proposed antenna. Since the proposed antenna provides an omnidirectional radiation pattern and ultra wide bandwidth for short distance communication between transmitting and the receiving antenna with low power consumption. By combining two spiral antennas with different radius of the radiation zone, the Standing Wave Ratio (SWR) can be kept low for a large bandwidth, resulting in an improved spiral antenna performance.