Antennas offering wide bandwidth, high gain and efficiency are essential to terahertz (THz) wireless communication systems and has gathered significant attention in antenna research. This paper introduces a compact, high-gain, ultra-wideband (UWB) microstrip patch antenna tailored for THz applications, along with its performance analysis. The proposed antenna has an elliptical patch with a pi shaped slot and is excited by a tapered feedline. An elliptical patch antenna incorporating a pi-shaped slot is introduced for the first time in the terahertz THz spectral region, demonstrating the ability to simultaneously achieve substantial size miniaturization, wideband performance, improved impedance matching, and enhanced gain. The antenna structure was designed and optimized for improved performance using CST Microwave Studio (MWS) version 2018. A Rogers RT/duroid 5880 substrate was used for antenna design, featuring 6 μm thickness, 2.2 relative permittivity, 0.0009 loss tangent, and 120 × 80 μm² planar dimensions. The proposed antenna demonstrates strong performance characteristics with a wide impedance bandwidth of 3.41 THz (5.01–8.42 THz), high gain of 7.906 dB, radiation efficiency of 77.83%, and low return loss of −43.57 dB, with consistent VSWR across the entire frequency range. The surface current distribution as well as the input impedance of the pi-shaped slotted antenna are also favorable. All the simulation results suggest that the proposed small size pi-shaped slotted elliptical patch antenna

can be a suitable candidate for high-speed 6G wireless communication applications in the THz band.