Xiang Guan

A 77-GHz Phased-Array Transceiver With On-Chip Antennas in Silicon: Receiver and Antennas

In this paper, we present the receiver and the on-chip antenna sections of a fully integrated 77-GHz four-element phased-array transceiver with on-chip antennas in silicon. The receiver section of the chip includes the complete down-conversion path comprising low-noise amplifier (LNA), frequency synthesizer, phase rotators, combining amplifiers, and on-chip dipole antennas. The signal combining is performed using a novel distributed active combining amplifier at an IF of 26 GHz. In the LO path, the output of the 52-GHz VCO is routed to different elements and can be phase shifted locally by the phase rotators. A silicon lens on the backside is used to reduce the loss due to the surface-wave power of the silicon substrate. Our measurements show a single-element LNA gain of 23 dB and a noise figure of 6.0dB. Each of the four receive paths has a gain of 37 dB and a noise figure of 8.0 dB. Each on-chip antenna has a gain of +2 dBi

A 77-GHz Phased-Array Transceiver With On-Chip Antennas in Silicon: Transmitter and Local LO-Path Phase Shifting

Integration of mm-wave multiple-antenna systems on silicon-based processes enables complex, low-cost systems for high-frequency communication and sensing applications. In this paper, the transmitter and LO-path phase-shifting sections of the first fully integrated 77-GHz phased-array transceiver are presented. The SiGe transceiver utilizes a local LO-path phase-shifting architecture to achieve beam steering and includes four transmit and receive elements, along with the LO frequency generation and distribution circuitry. The local LO-path phase-shifting scheme enables a robust distribution network that scales well with increasing frequency and/or number of elements while providing high-resolution phase shifts. Each element of the heterodyne transmitter generates +12.5 dBm of output power at 77 GHz with a bandwidth of 2.5 GHz leading to a 4-element effective isotropic radiated power (EIRP) of 24.5 dBm. Each on-chip PA has a maximum saturated power of +17.5 dBm at 77 GHz. The phased-array performance is measured using an internal test option and achieves 12-dB peak-to-null ratio with two transmit and receive elements active

A 24-GHz CMOS front-end

This paper reports the first 24-GHz CMOS front-end in a 0.18-/spl mu/m process. It consists of a low-noise amplifier (LNA) and a mixer and downconverts an RF input at 24 GHz to an IF of 5 GHz. It has a power gain of 27.5 dB and an overall noise figure of 7.7 dB with an input return loss, S/sub 11/ of -21 dB consuming 20 mA from a 1.5-V supply. The LNA achieves a power gain of 15 dB and a noise figure of 6 dB on 16 mA of dc current. The LNAs input stage utilizes a common-gate with resistive feedthrough topology. The performance analysis of this topology predicts the experimental results with good accuracy.

A fully integrated 24-GHz eight-element phased-array receiver in silicon

This paper reports the first fully integrated 24-GHz eight-element phased-array receiver in a SiGe BiCMOS technology. The receiver utilizes a heterodyne topology and the signal combining is performed at an IF of 4.8 GHz. The phase-shifting with 4 bits of resolution is realized at the LO port of the first down-conversion mixer. A ring LC voltage-controlled oscillator (VCO) generates 16 different phases of the LO. An integrated 19.2-GHz frequency synthesizer locks the VCO frequency to a 75-MHz external reference. Each signal path achieves a gain of 43 dB, a noise figure of 7.4 dB, and an IIP3 of -11 dBm. The eight-path array achieves an array gain of 61 dB and a peak-to-null ratio of 20 dB and improves the signal-to-noise ratio at the output by 9 dB.

A 24-GHz SiGe phased-array receiver-LO phase-shifting approach

A local-oscillator phase-shifting approach is introduced to implement a fully integrated 24-GHz phased-array receiver using SiGe technology. Sixteen phases of the local oscillator are generated in one oscillator core, resulting in a raw beam-forming accuracy of 4 bits. These phases are distributed to all eight receiving paths of the array by a symmetric network. The appropriate phase for each path is selected using high-frequency analog multiplexers. The raw beam-steering resolution of the array is better than 10deg for a forward-looking angle, while the array spatial selectivity, without any amplitude correction, is better than 20 dB. The overall gain of the array is 61 dB, while the array improves the input signal-to-noise ratio by 9 dB

Integrated Phased Array Systems in Silicon

Silicon offers a new set of possibilities and challenges for RF, microwave, and millimeter-wave applications. While the high cutoff frequencies of the SiGe heterojunction bipolar transistors and the ever-shrinking feature sizes of MOSFETs hold a lot of promise, new design techniques need to be devised to deal with the realities of these technologies, such as low breakdown voltages, lossy substrates, low-Q passives, long interconnect parasitics, and high-frequency coupling issues. As an example of complete system integration in silicon, this paper presents the first fully integrated 24-GHz eight-element phased array receiver in 0.18-/spl mu/m silicon-germanium and the first fully integrated 24-GHz four-element phased array transmitter with integrated power amplifiers in 0.18-/spl mu/m CMOS. The transmitter and receiver are capable of beam forming and can be used for communication, ranging, positioning, and sensing applications.

A fully integrated 24 GHz 8-path phased-array receiver in silicon

A fully integrated 8-channel phased-array receiver at 24 GHz is demonstrated. Each channel achieves a gain of 43 dB, noise figure of 8 dB, and an IIP3 of -11dBm, consuming 29 mA of current from a 2.5 V supply. The 8-channel array has a beam-forming resolution of 22.5/spl deg/, a peak-to-null ratio of 20 dB (4-bits), a total array gain of 61 dB, and improves the signal-to-noise ratio by 9 dB.

A 77GHz Phased-Array Transmitter with Local LO-Path Phase-Shifting in Silicon

A fully integrated 77GHz 4-element phased-array transmitter in 0.12mum SiGe BiCMOS based on a continuous local phase shifting approach is presented. Each element generates +12.5dBm output power at 77GHz and has 34dB gain from baseband to RF with a bandwidth of 2.5GHz. The chip demonstrates successful beam-steering at 77GHz

Phased array systems in silicon

Phased array systems, a special case of MIMO systems, take advantage of spatial directivity and array gain to increase spectral efficiency. Implementing a phased array system at high frequency in a commercial silicon process technology presents several challenges. This article focuses on the architectural and circuit-level trade-offs involved in the design of the first silicon-based fully integrated phased array system operating at 24 GHz. The details of some of the important circuit building blocks are also discussed. The measured results demonstrate the feasibility of using integrated phased arrays for wireless communication and vehicular radar applications at 24 GHz.

Multiple phase generation and distribution for a fully-integrated 24-GHz phased-array receiver in silicon

This paper presents an on-chip multiphase LO generation and distribution technique used to implement a fully-integrated 24-GHz 8-path phased-array receiver in silicon. Sixteen LO phases are generated by an LC ring oscillator and distributed by a symmetric network to all eight paths. The 8-path array achieves a phase shifting resolution of 22.5/spl deg/ and a total array gain of 61dB.