Christoph Wagner

A 77-GHz FMCW MIMO Radar Based on an SiGe Single-Chip Transceiver

This paper describes a novel frequency-modulated continuous-wave radar concept, where methods like nonuniform sparse antenna arrays and multiple-input multiple-output techniques are used to improve the angular resolution of the proposed system. To demonstrate the practical feasibility using standard production techniques, a prototype sensor using a novel four-channel single-chip radar transceiver in combination with differential patch antenna arrays was realized on off-the-shelf RF substrate. Furthermore, to demonstrate its practical applicability, the assembled system was tested in real world measurement scenarios in conjunction with the presented efficient signal processing algorithms.

PLL Architecture for 77-GHz FMCW Radar Systems with Highly-Linear Ultra-Wideband Frequency Sweeps

The successful implementation of a linear frequency modulated continuous wave (FMCW) radar transmitter is presented, consisting of a 77-GHz voltage controlled oscillator (VCO) and a 19-GHz down-converter manufactured in a 200-GHz silicon germanium (SiGe) technology. The influence of phase noise and frequency sweep linearity on the radar system performance is briefly described, and measurement results of these parameters are compared between different architectures

A Fully Differential 77-GHz Active IQ Modulator in a Silicon-Germanium Technology

A 77-GHz IQ modulator in a fully differential circuit configuration is presented. It includes an local oscillation (LO) buffer amplifier, a medium-power output stage, a double-balanced active mixer architecture and on-chip baluns for easy characterization. A differential branch-line coupler provides quadrature phase signals at the upconversion mixer LO inputs. The circuit is manufactured in a 200-GHz transit frequency technology, and the circuit performance is shown by on-wafer measurements.

A Low-Power Low-Noise Single-Chip Receiver Front-End for Automotive Radar at 77 GHz in Silicon-Germanium Bipolar Technology

This paper presents a single chip receiver front-end, including low-noise amplifier and mixer, for application in automotive radar systems at 77 GHz. The circuit has been implemented in a SiGe HBT technology. The complete circuit occupies 1030 times 1130 mum2 including bond pads and dissipates 440 mW from a 5.5 V supply. The front-end shows a minimum measured single sideband noise figure (SSB NF) of 11.5 dB and a maximum conversion gain of 30 dB at 77 GHz. Linearity measurements show a 1 dB input compression point of -26 dBm and a third order intercept point of -21.6 dBm at 77 GHz.

A 79-GHz radar transceiver with switchable TX and LO feedthrough in a Silicon-Germanium technology

This contribution shows the successful implementation of a fully-differential single-chip radar transceiver with switchable transmit path. The chip facilitates cascading of multiple modules via daisy-chaining using the integrated LO power splitter and LO output on the chip edge opposite to the LO input (LO feedthrough). An on-chip differential rat-race coupler provides for separation of transmit (TX) and receive (RX) paths, therefore only a single antenna port is required. The circuit performance is demonstrated in on-board measurements.

A phased-array radar transmitter based on 77-GHz cascadable transceivers

A 77-GHz phased-array radar transmitter that is based on fully integrated, differential, cascadable transceiver circuits is presented. The building blocks of the 77-GHz IQ transceiver are explained in detail, along with measurement results of the transmitter part. A demonstration of the beam-forming capability of the presented transceiver is given using a 4-channel phased-array radar demonstrator that incorporates the generation of PLL stabilized 77-GHz signals.

A Low-Power Micromixer with High Linearity for Automotive Radar at 77 GHz in Silicon-Germanium Bipolar Technology

A direct-conversion micromixer realized in a modern SiGe:C bipolar technology for application in automotive radar systems at 77 GHz is presented. The mixer exhibits a minimum conversion gain of 15 dB and a maximum noise figure of 16.5 dB over a frequency range from 75 GHz to 85 GHz. The 1dB input related compression point is at -3dBm and the RF and LO matching is better than -20 dB and -10 dB, respectively. The total DC current consumption is 34 mA at 5.5 V

A 77GHz automotive radar receiver in a wafer level package

In this paper, a 77-GHz radar receiver is presented, which comes in a wafer level package and thus eliminates the need for wire bonding yielding significant cost reduction. The high integration level available in the productive Silicon-Germanium (SiGe) technology used in this paper allows for implementation of in-system monitoring of the receiver conversion parameters. This facilitates the realization of ISO 26262 compliant radar sensors for automotive safety applications.

A 366mW direct digital synthesizer at 15GHz clock frequency in SiGe Bipolar technology

A direct digital synthesizer (DDS) with 6-bit amplitude and 8-bit phase resolution is presented. The phase-to-amplitude mapping circuit is implemented as a differential pair in saturation. The suitability of this circuit for broadband application and high temperature range is shown. The use of a modern SiGe bipolar technology enables both a low power consumption of 366mW and a high clock frequency of 15GHz. A spurious free dynamic range (SFDR) between 42 and 20 dBc is achieved. The chip is fabricated in a 0.35 µm 200-GHz fT SiGe bipolar technology and occupies only 1024×1128 µm2.

An area and phase noise improved 19-GHz down-converter VCO for 77-GHz automotive radar frontends in a SiGe Bipolar Production Technology

A down-converter including a voltage controlled oscillator (VCO), buffer, mixer, and prescaler is presented. The fully differential circuit configuration of the down-converter operates in a frequency range from 17.7 GHz to 19.4 GHz at a 5.5 V supply. The overall current consumption at room-temperature is 186 mA. The VCO has been improved in terms of area consumption and phase noise.