A 2×2, 316 GHz SiGe scalable transmitter array with novel phase locking method and on-die antennas

We demonstrate a fully integrated 2×2 SiGe transmitter array at 316 GHz. A novel method is introduced to phase-lock the high frequency signal sources without any additional circuitry. This method suppresses the other possible oscillatory modes automatically. The power of the locked signal sources are combined in the air by the 2×2 on-chip antenna array which are fed with the locked sources. This array is scalable to larger sizes in the same layout style. This array transmitter utilizes Colpitts oscillators as high frequency signal sources; however, this method can be applied to any other oscillator architecture to perform the frequency and phase locking. The frequency of this transmitter follows the simple equations for a single Colpitts oscillator, thereby facilitating the design of the circuit.