Compact Dual-Band High-Gain MIMO Antenna with Multi-stage Notched Microstrip Design for Sub-THz Communications

This paper presents a compact two-port MIMO antenna designed for 0.1—1 THz applications. The antenna features a multi-stage notched microstrip patch, fed by a 50-ohm line with a 0.02 mm feed width, built on a polyimide substrate (thickness: 0.04mm, εr=4.3, loss tangent=0.004). With a footprint of 0.4× 0.79 mm2, it resonates at 0.372 THz and 0.762 THz, offering bandwidths of 20 GHz and 60 GHz. Simulations using HFSS v15 show return losses of –30.73 dB and –31.76 dB, VSWRs of 1.06 and 1.05, and high gains of 5.00 dBi and 13.30 dBi. The design ensures strong isolation (ECC<0.02), making it suitable for compact, high-gain THz MIMO systems.