Performance Analysis of a Compact Dual-band UWB Patch Antenna for Biomedical Applications

Wireless Capsule Endoscopy (WCE) shows a tremendous prospect in biomedical applications as it exhibits effectiveness in GI tract related diagnostics in a non-invasive way. Antenna integrated into an in-body WCE transmitter plays an important role for transmitting images of GI tract of human bodies wirelessly to an outer-body receiver. Despite recent improvement of antenna design, there are still shortcomings such as lower bandwidth and large antenna size. Main motivation of the paper is to design a dual-band UWB antenna, particularly focusing on reducing antenna geometry and increasing bandwidth efficiency in order to improve the overall effectivity of WCE system. Circular path antenna miniaturization and bandwidth improvement techniques are exploited for obtaining the optimum antenna which has a volume of 32.4 mm
³
(10 mm $\times 10$ mm $\times 0.324$ mm). A homogeneous muscle tissue is considered as a human body phantom for the design and Roger RT 5880 is used as the substrate material for the antenna. The antenna operates in two bands: lower band from 3.13 GHz to 3.6 GHz, and upper band from 5.87 GHz to 10.512 GHz. Results illustrate lower directivity of the antenna in both E-plane and H-plane. Maximum input power of 178 mW can be applied to the proposed antenna for limiting SAR value under the specific value (2W/kg) mentioned in IEEE C95.1-1999 safety standards.