Single Flip-Chip Packaged Dielectric Resonator Antenna for CMOS Terahertz Antenna Array Gain Enhancement

A single dielectric resonator antenna (DRA) capable of enhancing the antenna gain of each element of a
$2\times 2$
terahertz (THz) antenna array realized in a 0.18-
$\mu \text{m}$
CMOS technology is proposed in this paper. The DRA implemented in a low-cost integrated-passive-device technology is flip-chip packaged onto the CMOS antenna array chip through low-loss gold bumps. By designing the DRA to work at the higher order mode of TE
$_{3,\delta,9}$
, only a single DRA, instead of conventionally needing four DRAs, is required to simultaneously improve the antenna gain of each element of the
$2\times 2$
antenna array. This not only simplifies the assembly process, but it can also reduce the assembly cost. Moreover, the DRA can provide great antenna gain enhancement because of being made of high-resistivity silicon material and higher order mode operation. The simulated antenna gain of each on-chip patch antenna of the
$2\times 2$
CMOS antenna array can be increased from 0.1 to 8.6 dBi at 339 GHz as the DRA is added. To characterize the proposed DRA, four identical power detectors (PDs) are designed and integrated with each element of the
$2\times 2$
THz antenna array. By measuring the voltage responsivity of each PD output, the characteristics of each antenna of the antenna array with the proposed DRA, including the gain enhancement level and radiation pattern, can be acquired. The measurement results match well with the simulated ones, verifying the proposed DRA operation principle. The four PDs with the proposed DRA are also successfully employed to demonstrate a THz imaging system at 340 GHz. To the best of our knowledge, the proposed DRA is the one with the highest order operation mode at THz frequencies reported thus far.