Dummy Metal Aware Tunable On-chip Slot Antenna with A Low-cost Proof-of-Concept

Shift in resonance frequency due to insertion of dummy metal fills by CMOS foundry is one of the major challenges in designing an on-chip antenna at microwave frequencies. The other important challenge is to reduce the area occupied by the on-chip antenna in order to minimize the fabrication cost. To address both these problems, a single solution topology is proposed consisting of an on-chip slot resonator in shunt with a MOS varactor. After fabrication process, the MOS varactor is capable of tuning the resonant frequency by application of external bias voltage. Additionally, the zero bias capacitance offered by the MOS varactor is used to lower the resonance frequency for the same physical area of the antenna. A CPW to microstrip line transition is designed to excite the slot. The antenna operates at 2.45 GHz and occupies an area of 3 mm × 1.2 mm. Subsequently, measured results are presented to validate the simulation results for a low cost proof-of-concept design.