Mahdi Bagheri

A CMOS quadrature oscillator with deterministic output sequence

Quadrature oscillators usually suffer from output signal phase ambiguity. A modified quadrature oscillator is proposed, where the output sequence is deterministic. Simulation and measurements show that the modified QOSC has little degradation in phase noise or increase in power consumption, and has a unique output sequence. The circuit dissipates 6 mW and tunes from 1.37 to 1.85 GHz.

A 71–86-GHz Phased Array Transceiver Using Wideband Injection-Locked Oscillator Phase Shifters

This paper presents the first phased array transceiver operating from 71 to 86 GHz using injection-locked oscillators (ILOs) for phase shifting. A folded-cascode ILO is proposed to extend the locking range of an array of oscillators. Frequency multiplication covers a 10-GHz tuning range with 23-dB power gain. Each ILO path covers more than ±300° and exhibits low amplitude variation with respect to phase shift range (<1 dB) and excellent isolation and amplitude error (<0.5 dB) between array elements. A wideband, bidirectional RF front end delivers 10-dBm maximum output power with more than 20-dB conversion gain over the 3-dB bandwidth in the transmit (TX) mode and a minimum 9.5-dB noise figure with more than 20-dB conversion gain in the receive (RX) mode. Low phase noise is demonstrated in the ILO approach over the phase tuning range with −112 dBc/Hz at 1-MHz offset and phase noise variation for different phase shift states under 2.5 dB, corresponding to less than 2° phase error. Array patterns demonstrate the wide scan range, and dynamic measurements show that the transmitter supports up to 6-Gb/s data rate with 256 QAM. The chip has

Wide tuning range CMOS LC quadrature oscillators based on quadrature mode switching

3.4\times2.1

An E-band, scalable 2×2 phased-array transceiver using high isolation injection locked oscillators in 90nm SiGe BiCMOS

mm2 area implementing in the 90-nm BiCMOS technology and consuming 386.4 mW in the TX mode and 286 mW in the RX mode per element.

CMOS LC quadrature oscillators with enhanced tuning range by selective mode switching

A general method for designing a wide tuning range CMOS LC quadrature oscillators (QOSC) is introduced. A design example of a QOSC with switchable quadrature oscillation mode is presented. The effective tuning range is 89% for a 1.4 GHz example.

Tuning-Range Enhancement Through Deterministic Mode Selection in RF Quadrature Oscillators

This paper presents the first E-band phased array transceiver that uses injection locked oscillators (ILOs) for beamforming. We propose a current injection distribution network with wide locking range and high isolation. A 2×2 bidirectional transceiver is demonstrated to operate from 71-86 GHz and measurements verify that each oscillator can be controlled independently with phase shift over ±300 degrees with <; 5° phase error and under 0.9 dB amplitude variation. Each channel has a 9.5-dB noise figure in RX mode and a 10-dBm output power in TX mode. The phase noise of the locked oscillator exhibits less than 2.5 dB variation across the phase steering range. The 90-nm SiGe BiCMOS chip consumes 386.4 mW in TX mode and 286 mW in RX mode per channel.

Wideband circuits and methods

Quadrature oscillators (QOSCs) can operate in two selective modes of quadrature oscillation. By controlling the mode of oscillation, different wide tuning range CMOS LC QOSCs have been designed. The measured tuning range is 60% for 3.7 GHz design and 94% for 1.3 GHz design. Phase noise measurement shows that by this modified series coupled QOSC (S-QOSC) a FOMT (figure of merit with tuning range) of 199 dB can be achieved.

Systems and methods of calibrating a transmitter

Quadrature oscillators (QOs) based on parallel or series coupling mechanisms produce ambiguous phase relationships between the coupled oscillators. Deterministic mode selection is presented and analyzed for a series-coupled LC quadrature oscillator ( LC-QO) and leveraged to increase the tuning range of the QO. Series-coupled LC-QOs have been implemented in a 90-nm CMOS technology. Measured results show a frequency tuning range of 94% for a center frequency of 1.3 GHz, 60% for the oscillator operating at 3.7 GHz, and 52% for the oscillator operating at 4.4 GHz.