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A complementary metal oxide semiconductor (CMOS) voltage‐controlled oscillator (VCO) using a tail current source modulated with the output frequency is presented to achieve low phase noise with low power consumption at the K‐band. Differentially modulated current sources, which reduce flicker noise by the feedback of the VCO outputs, contribute to an overall reduction in the phase noise of the VCO using the electromagnetic‐based fully symmetrical design. The proposed LC VCO with a 3‐bit switched capacitor bank for a wide tuning range was fabricated on the size of 0.4 × 0.57 mm2 using a 65‐nm CMOS process. The measurement results of the proposed VCO showed a frequency tuning range from 22.57 to 25.3 GHz, and a phase noise of −108.48 dBc/Hz at a 1‐MHz offset frequency with a power consumption of 8.27 mW at a supply voltage of 1.2 V. The calculated figure of merit (FoM) and FoM with the tuning range were −186.48 and −187.67 dBc/Hz, respectively. [ABSTRACT FROM AUTHOR]

A folded dipole antenna using an artificial magnetic conductor (AMC) structure is proposed to improve the frequency bandwidth and reduce the size of the antenna on a chip. To change the distribution of the electromagnetic (EM) field, the proposed AMC structure shaped with square‐in‐square rings (SSRs) is arranged along the radiating metal of the folded dipole antenna and implemented on the lowermost metal layer of the backend oxide layers (BEOLs) between the radiating metal of the top layer of the BEOL and the ground plane of the bottom of the substrate. The SSR of the proposed antenna‐on‐chip (AoC) widens the frequency bandwidth by varying the electrical length to the ground and reduces the physical size of the radiating metal by increasing the effective permittivity. The 3D EM‐wave simulation shows that the proposed AMC structure changes the distribution of EM‐wave in the BEOL and Si substrate such that more EM fields are condensed around the radiating metal and the electrical length to the ground is nonuniform and longer. The AoC with the proposed AMC structure was fabricated using a 65‐nm standard complementary metal‐oxide semiconductor process with one‐poly and nine‐metal. Compared with the conventional 150‐GHz antenna that was implemented on the same die, the proposed differential antenna was measured to be a −10 dB bandwidth of 46 GHz, with a 1.12‐times improvement, and a size reduction of 20.4%. The measured gain of the proposed antenna was −5.99 dBi including the passive balun with an insertion loss of −1.36 dB in simulation. [ABSTRACT FROM AUTHOR]

This study proposed a method for distinguishing the baseband signal for each frequency in two‐tone radar systems using the difference in the number of peaks of the envelope detected signal. The proposed method is based on the characteristic that the baseband signal for each frequency exhibits a different number of peaks, depending on the operating frequency, at a fixed sampling frequency in data acquisition. The phase difference between the transmitting and receiving signals for each frequency can be obtained using envelope detection of the baseband signals in two‐tone radar systems, and the proposed method can effectively match the phase difference and operating frequency without using additional controls and synchronization. This simplifies the procedure to estimate the absolute range up to the maximum unambiguous range, corresponding to a phase difference of 2π. Measurement results demonstrate that the absolute range, using a two‐tone radar with a frequency spacing of 150 MHz, can detect the distance with an accuracy of 97.8% up to the maximum unambiguous range using the proposed method. [ABSTRACT FROM AUTHOR]