A 510-to-545 GHz Radiating Source With an SIW-Based Harmonic Power Extractor in 40-nm CMOS

This article analyzes the required fundamental-frequency load impedance for third harmonic enhancement in a common-source transistor through investigating the relationship between the third harmonic current, the fundamental-frequency voltage, and the real and imaginary parts of the fundamental-frequency load impedance in the common-source transistor. Then, a harmonic power extractor (HPE) based on a differential substrate-integrated waveguide (SIW) is proposed to provide the required load impedance of the tripler at both the output and fundamental frequencies, thus enhancing the third harmonic power generation of the tripler. The HPE also provides the suppression of unwanted lower order harmonic leakage of the radiating source. In this article, the operation principle of the SIW-based HPE is explained, and the design of a 0.52-THz CMOS radiating source with the SIW-based HPE is detailed. After that, the mechanism of the bulk-bias-control-based frequency tuning technique used in the radiating source is analyzed, and the method of avoiding the parasitic radiation from the oscillator tank of the radiating source is introduced. In measurement, the radiating source achieves
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1-dBm equivalent isotropically radiated power,
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21.8-dBm radiated power, and 0.32% dc-to-THz efficiency at 524 GHz with a dc power consumption of 20.7 mW under a 0.9-V supply voltage. By using both power supply tuning and bulk bias tuning, the radiating source achieves 6.6% frequency tuning range.