This letter presents a 28 GHz low insertion loss and compact size 4-bit phase shifter in 65 nm CMOS Technology. In order to get low insertion loss and compact size, this phase shifter is composed of two types of passive phase shifters, high-pass/low-pass type and switched filter type. Various techniques are used such as triple well body-floating, gate-floating, removal of capacitance of the off-state transistor using resonant inductor, and minimized interconnection line which is based on matching network. This phase shifter has 6.36 dB of average insertion loss over the 27.5-28.35 GHz, and loss variation is about 2 dB. The return loss is higher than 12 dB, RMS phase error is 8.98 ^° , OIP3 is 8.1 dBm at -10 dBm input power and its core size is 636 μm × 360 μm. To the authors' knowledge, these results are the state of the art in CMOS passive phase shifters in K-band frequency.

This paper presents a 16-element phased-array receiver for 76-84-GHz applications with built-in self-test (BIST) capabilities. The chip contains an in-phase/quadrature (I/Q) mixer suitable for automotive frequency-modulation continuous-wave radar applications, which is also used as part of the BIST system. The chip achieves 4-bit RF amplitude and phase control, an RF to IF gain of 30-35 dB at 77-84 GHz, I/Q balance of and at 76-84 GHz, and a system noise figure of 18 dB. The on-chip BIST covers the 76-84-GHz range and determines, without any calibration, the amplitude and phase of each channel, a normalized frequency response, and can measure the gain control using RF gain control. System-level considerations are discussed together with extensive results showing the effectiveness of the on-chip BIST as compared with standard S-parameter measurements.

A K-band CMOS voltage-controlled oscillator (VCO) is implemented with a 0.18- ¿m radio frequency CMOS process. For low supply voltage operation, a transformer-feedback topology using a transformer is proposed. The analysis of the transformer-feedback VCO is presented. This shows that the inductance ratio of the transformer must be optimized, and asymmetric-width transformers allow the easy optimization and the high Q-factor. Based on this analysis, the transformer design consideration of the transformer feedback VCO is presented. The VCO operates at 24.27 GHz with the phase noise of -100.33 dBc/Hz at 1-MHz offset, and it consumes 7.8 mW from a 0.65-V supply voltage.

A simultaneous measurement method of the thickness and permittivity of a thin and uniform material which is attached onto the top of a sensor structure is presented. The sensor utilizes the fundamental and harmonic frequencies of a microstrip line ring resonator structure. The thickness and permittivity of a material under test are calculated from two simultaneous equations at the fundamental and second-harmonic frequencies. Fitting equations to calculate the peak resonant frequencies with respect to the thickness and permittivity are also derived. The structure is implemented with a microstrip line on the front side of a TLY-5A substrate and coplanar waveguide access lines on the backside. The permittivity and thickness of the test material are successfully measured simultaneously.

This paper presents a 16-element Q-band transmit/ receive phased array with high receive linearity and low power consumption. The design is based on the all-RF architecture with passive phase shifters and a 1:16 Wilkinson network. An input P_1dB from -9 to -10 dBm and a noise figure of 10-11.5 dB at 44-46 GHz is achieved in the receive mode with a power consumption of 0.95 W. In the transmit mode, each channel has an output P_1dB of 3-2 dBm and P_sat of 6-4 dBm at 44-46 GHz with a power consumption of 1.16 W. The design results in a low root mean square (rms) gain error due to a high-resolution variable gain amplifier in each channel. Measurements on multiple channels show near-identical gain and phase response in both the transmit and receive mode due to the use of a symmetrical passive combiner. The measured on-chip coupling is <; -40 dB and results in insignificant additional rms and phase error.