Conformal MIMO Ultrawideband Antenna Design for High-Speed Wireless Telemetry in Capsule Endoscopy Systems
Liu Chang, Amjad Iqbal, Abdul Basir, Roy B. V. B. Simorangkir, Ismail Ben Mabrouk
Abstract
This article presents a novel ultrawideband (UWB) antenna for multiple-input-multiple-output (MIMO) operations in wireless capsule endoscopy (WCE) applications. The design is capable of supporting high channel capacity for real-time transmission and addressing the frequency detuning effect. Thanks to the conformal meander structure, the design efficiently uses the inner wall space of the capsule, achieving both compactness and wideband operation. The proposed MIMO antenna consists of two elements, each occupying a volume of 7.192 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup>. The experimental measurements are performed inside a minced pork meat. The antenna covers a bandwidth range from 0.61 to 1.51 GHz, achieving a fractional bandwidth (FBW) of 84.91% and a peak gain of −30.4 dBi. An isolation level greater than 20 dB is maintained, indicating low mutual coupling between MIMO antenna elements. The specific absorption rate (SAR) is evaluated to be 0.0202 W/kg at a transmitted power of −16 dBm, and the link margin (LM) is calculated to be 20 dB at a distance of 2 m. Therefore, the proposed bio-telemetry system confirms its suitability for safe and high data rate communications.