A 280-GHz Lensless Triple-Push Radiator With Source-Combining Technique

This letter presents a terahertz (THz) lensless source-combining triple-push (SCTP) radiator. By combining the three-phase outputs through the transistor source nodes, large 3<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rd</sup>-harmonic components are introduced in both gate-to-source and drain-to-source voltages, significantly enhancing the amplitude of the 3<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rd</sup>-harmonic current (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$I_{{\mathrm d\_3\mathrm f0}}$</tex-math> </inline-formula>) and resulting in high output power and dc-to-THz efficiency. Fabricated in 65-nm CMOS, the 272.3-to-281.3-GHz radiator prototype delivers an effective isotropic radiated power (EIRP) of −2.26 dBm and a radiated power (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$P_{\textrm {rad}}$</tex-math> </inline-formula>) of −8.46 dBm at 279.7 GHz, without using a silicon lens. The radiator consumes 56.9 mW and achieves a high dc-to-<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$P_{\textrm {rad}}$</tex-math> </inline-formula> efficiency of 0.25%.