Power distribution to multiple implanted sensor devices using a multiport bandpass filter (BPF) approach

This paper presents a magnetically coupled bandpass filter (BPF) approach for power distribution to multiple implanted devices. The BPF design approach accounts for the multiple loads and enables maximum power transfer into each individual receiver for given coupling coefficients between the coils. The proposed concept is demonstrated by showing power distribution to two identical receivers below biological tissue through an external repeater on the tissue surface. In order to mimic biomedical implants, the test structure is fabricated using 25 μm thick liquid crystal polymer (LCP) substrates covered with a surrogate for biological tissue. The power transfer efficiency (PTE) distributed to each receiving unit is measured as 20.7 % for each of two devices while the total power transfer to a single receiver shows an efficiency of 42.2 % indicating that the power distribution only causes a power loss of 0.8 %. Therefore, the results imply the utility of the proposed design approach for power distribution to a network of biomedical implants.