A Broadband and High-Efficiency Microbump Antenna-on-Chip Based on Parasitic-Mode Control With Ultra-Thin Substrate

Microbump antenna offers a viable antenna-on-chip (AoC) solution to achieve high radiation efficiency using standard semiconductor processes. This paper presents a feasible method for broadening the bandwidth of terahertz microbump antenna while preserving its high efficiency. Instead of introducing additional microbump structures, two pairs of lossy parasitic strips are used to introduce high-efficiency parasitic resonance, while enabling differential mode in each strip pair to mitigate the in-band gain deterioration. The proposed antenna is fabricated using the 65 nm complementary metal-oxide-semiconductor (CMOS) process and the standard flip-chip technology. Compared with the existing on-chip microbump antennas, the proposed method enhances the bandwidth from 2.8% to 5.7%, achieving an efficiency of 42% and a gain of 3.85 dBi on a substrate with a thickness of 0.006λ₀, providing an implementable solution for high-performance AoCs for sub-terahertz integrated circuits.