Six-Port Direct Modulator With Carrier Suppression Technology for High-Speed High-Frequency Wireless Communications

In this letter, a six-port direct modulator with carrier leakage suppression is proposed and experimentally demonstrated for downlinks in the future high-speed high-carrier-frequency wireless communication systems. To handle high carrier frequencies and provide good performance, GaAs metal-semiconductor field-effect transistor RF switches are used to complete the modulation. Up to 500-MBd quadrature phase shift keying signals at 24 GHz are generated and evaluated in our system. Moreover, the proposed six-port modulator is easy to integrate with the optical link and modulated signals at 24 GHz are evaluated after transmission over up to 20-km standard single mode fiber.