A 220-GHz Planar Triangular Lattice Transmitter Array With 42.7-dBm Peak EIRP for Long-Distance High-Data-Rate Wireless Communication

In this article, we develop a 220-GHz planar triangular lattice transmitter (TX) array for achieving a super high effective isotropic radiated power (EIRP), addressing the challenges associated with long-distance and high-data-rate wireless communication in the terahertz (THz) band. Due to the confliction between the electrical large size THz chips and limited space among them, only a few THz arrays operating above 200 GHz have been reported, with most of them adopting a 1-D array configuration to satisfy the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda $ </tex-math></inline-formula>/2 spacing requirement. This makes it challenging to achieve a high-quality radiation beam, high EIRP, and a 2-D scalable planar array. To overcome those challenges, a 2-D triangular lattice array is proposed and derived using the array factor (AF) formula, and subsequently utilized in the design of a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4\times 4$ </tex-math></inline-formula> TX array integrated with a multilayer waveguide package. Consequently, distinct advantages are obtained, including enhanced EIRP and scalability. As a proof-of-concept, a 220-GHz <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4\times 4$ </tex-math></inline-formula> TX array was developed and fabricated by employing hybrid technologies, including a 130 nm silicon-germanium bipolar junction transistor and the complementary metal-oxide-semiconductor transistor (SiGe BiCMOS) process, a full-metal micromachining process, and a multilayer printed circuit board (PCB) technology. Experimental results demonstrate that the developed TX array achieves a peak EIRP of 42.7 dBm with a 3-dB radio frequency (RF) and width of 40 GHz, supporting a real-time wireless communication data rate of 18 Gbps with 16-quadrature amplitude modulation (QAM) at 100 m. The proposed TX array demonstrates several advantages, including a super high EIRP, extended communication range, high data rate, low cost, high integration, and compact size, making it well-suited for the THz wireless communication systems.