Wide Impedance-Bandwidth and Gain-Bandwidth Terahertz On-Chip Antenna With Chip-Integrated Dielectric Resonator

A wide impedance-bandwidth and gain-bandwidth terahertz (THz) on-chip antenna (OCA) with chip-integrated dielectric resonator (CIDR) backed by a ground plane is proposed in this article. The antenna uses the inherent silicon substrate in complementary metal-oxide-semiconductor (CMOS) technologies as a rectangular dielectric resonator (DR), that is, the CIDR. This CIDR can be seen as a standard dielectric resonator antenna (DRA) or a magnetic wall cavity with in-phase reflected waves from the ground. A versatile comb-shaped dipole antenna is designed above the silicon CIDR, functioning both as a feeder for the DRA and an independent radiator. With the proper design of the CIDR and the dipole, multiple higher order DR modes and the cavity mode are simultaneously excited, namely, hybrid DR-cavity modes. The hybrid modes greatly expand the bandwidth and improve the gain. Simulations show that the -10 dB impedance bandwidth and 3 dB gain bandwidth are 50% and 34.5%, respectively, while a peak gain of 6.5 dBi is achieved at 305 GHz. For validation, the antenna is fabricated using the Taiwan Semiconductor Manufacturing (TSMC) 65 nm CMOS technology and tested by dedicated THz measurement setups. The fabricated sample shows a peak gain of 8.6 dBi and a maximum radiation efficiency of 44% at 295 GHz. Meanwhile, low cross-polarization levels and stable patterns are also observed. The features of wide bandwidth, high gain, and low profile make the antenna a good candidate in fully integrated THz transceiver systems. To the best of the authors' knowledge, this is the widest fully integrated OCA working at THz frequencies.