A resonance circuit is interposed between a base and a collector of an oscillating transistor and is configured such that a resonance frequency is switched in correspondence with two different frequency bands. Kits comprise, for example, a guide element and an immobilization element of a biocompatible material with a size and shape suitable for placement within the sacroiliac joint. The sensor chip is provided on the diaphragm for outputting an electrical signal in proportion to the deformation of the diaphragm.