A wireless communication system is disclosed herein. The source side semiconductor is made of a high mobility semiconductor material, and the drain side semiconductor is made of a low leakage semiconductor material. The tunneling junction solar cell includes a base layer, a quantum-tunneling-barrier layer situated above the base layer, an emitter layer, a front-side electrode, and a back-side electrode. One element Ca is coupled to the output shaft 3 via the first gear row G1.