Abstract
In this letter, we propose a 32-42-GHz frequency quadrupler that performs digital logic operations between four phase-shifted differential signals at one-fourth of the output frequency. The four phase-shifted signals are generated via a 10-GHz rotary traveling-wave oscillator (RTWO) and are symmetrically routed to the quadrupler using a CMOS buffered clock tree. The harmonic rejection ratio (HRR) is enhanced by employing a differential LC filter tuned at its output center frequency. The proposed frequency quadrupler is implemented in 22-nm FD-SOI CMOS. At 37 GHz, it produces an output power of -4 dBm with a 10% drain efficiency. It consumes 4 mW from 0.8-V supply and occupies a core area of 0.021 mm2. The worst-case HRR for fundamental, second, third, and fifth harmonics are 41.3, 48.6, 41.3, and 37.3 dBc, respectively.
Highlights
M ILLIMETER-WAVE radars in the 77–81-GHz band have recently garnered high interest due to their use in advanced driver assistance systems (ADASs) and their potential for autonomous driving
We introduce a new logic-based frequency quadrupler that combines four complementary square-wave pulses that can be effectively produced from a co-located 10-GHz rotary traveling-wave oscillator (RTWO) in order to generate an output signal at 40 GHz with a good harmonic rejection of RTWO harmonics
The EC NAND–OR logic is loaded with a differential tracking filter LT -CT [see Fig. 2(b)] that is tuned to the fourth harmonic and drives the 40-GHz output buffer, placed outside the RTWO, through a differential transmission line (TL)
Summary
M ILLIMETER-WAVE (mmW) radars in the 77–81-GHz band have recently garnered high interest due to their use in advanced driver assistance systems (ADASs) and their potential for autonomous driving. Cascading of frequency doublers is not power-efficient as they require carefully designed interstage matching circuits in order to reject unwanted spurious harmonics [1]–[3]. It is not area-efficient, as the isolation between them needs to be maintained in order to avoid subharmonic coupling. Another way is to use a frequency quadrupler. By a frequency doubler to generate the LO signal in the 77–81-GHz radar band
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