RF characteristics of wireless capsule endoscopy in human body

The wireless capsule endoscope, as a small electronic device, has conquered some limitations of traditional wired diagnosing tools, such as the uncomfortableness of the cables for the patient and the inability to examine the very convoluted small intestine section. However, this technique is still encountering a lot of practical challenges and is looking for feasible improvements. This work investigates the RF performance of the wireless capsule endoscope system by studying the electromagnetic (EM) wave propagation within the human body. A wireless capsule endoscopy transmission channel model is constructed to serve the purpose of investigating signal attenuations according to the relative position between the transmitter and the receiver. Within 300-500 MHz, the S21 results are regular and do not display any sudden changes, which allows a suitable expression to be derived for S₂₁ in terms of frequency and offset. The results provide useful information for capsule localization.