UC San Diego

Recent increase in the demand for low latency and high data rate wireless links is the main reason for the rapid advancement in >100 GHz millimeter-wave systems especially D-band (110-170 GHz) communication links. Emerging applications such as virtual/augmented reality (VR/AR), high speed backhaul communication and the Internet of Things (IoT) now have greater opportunities.

The first contribution of this thesis is the development of the world’s first 140 GHz 128-element fully 2D scalable wafer-scale dual receive phased array in CMOS technology. In the first contribution, the wafer-scale beamformer chip is composed of 128 RX channels for an 8×8 dual-polarized array. RF beamforming is employed with 4-bit phase and gain controls on every element, and on-chip dual down-converters are used for an intermediate-frequency (IF) interface at 9-14 GHz. Also, a ×6 local-oscillator (LO) multiplier chain is used and two 64:1 Wilkinson combiners are employed for the RF distribution network with signal amplification within the combining network. The chip is flipped on a low loss organic interposer (RF PCB) containing the RF transitions, LO, and IF distribution networks, and which feeds an 8×8 dual-polarized microstrip antenna array with a spacing of 0.57 λ×0.57 λ (at 140 GHz) in the horizontal and vertical directions. The array scans to ±45 ◦in all planes for both polarizations, and the measured response supports 64 QAM operation with 2×55 Gb/s links, and achieving > 100 Gb/s links from a single aperture.

The second contribution is a scalable 8x8 transmit and receive array phased array at D-band. Its grid size is maintained close to (or equal) λ /2 at 140 GHz in both x- and y-directions, hence achieving a wide electronic scanning angle of up to 60 ◦. The measured peak effective isotropic radiated power (EIRP) of the TX array is 34-37.5 dBm at 137.5-145 GHz which is the highested reported EIRP so far for silicon technologies. Communication link measured for both TX and RX operations supports modulated 16-/64- quadrature amplitude modulation (QAM) signals with up to 16 Gb/s data rates with an rms EVM less than 7 %/6 % respectively, in a room and up to 5.2 m distance between the Tx and Rx phased-arrays.

The third contribution is the development of a 16x16 element Ka-Band reflector array. A new analysis method is presented to illustrate the effect of multiple reflections between the passive phase shifter and the antenna, and it is based on an S-parameter analysis. Simulations show that it is critical to have a well matched antenna for good operation of reflect arrays and with low phase errors. The presented design can scan to +/-70 ◦. in all planes and in both polarizations.