Jürgen Hasch

Millimeter-Wave Technology for Automotive Radar Sensors in the 77 GHz Frequency Band

The market for driver assistance systems based on millimeter-wave radar sensor technology is gaining momentum. In the near future, the full range of newly introduced car models will be equipped with radar based systems which leads to high volume production with low cost potential. This paper provides background and an overview of the state of the art of millimeter-wave technology for automotive radar applications, including two actual silicon based fully integrated radar chips. Several advanced packaging concepts and antenna systems are presented and discussed in detail. Finally measurement results of the fully integrated radar front ends are shown.

Second generation transceivers for D-band radar and data communication applications

A single chip, dual-functionality radio and FMCW radar transceiver, operating at 140 GHz is described. Doppler, loop-back, and 4Gb/s NLOS radio link demos, over the air and at distances exceeding one meter, are demonstrated. The second part of the paper presents novel, sub-1.8 V circuit topologies intended for a low power, high resolution 120 GHz radar transceiver with self-calibration capabilities. The measured receiver noise figure, gain, and phase noise are 7.5 dB, 20 dB, and −100 dBc/Hz@1MHz offset, respectively.

A study of SiGe signal sources in the 220–330 GHz range

This paper investigates fundamental and push-push SiGe HBT voltage-controlled-oscillator topologies with and without doublers, as possible solutions for efficient milliwatt-level, low-noise signal sources at sub-millimeter wave frequencies. A fundamental frequency Colpitts VCO covers the 218-246 GHz range (the highest for SiGe HBTs) with up to -3.6 dBm output power and 0.8% efficiency. A Colpitts-Clapp VCO-doubler shows -1.7 dBm output power around 290 GHz, a record -101 dBc/Hz phase noise at 10 MHz offset, 7.5% tuning range and 0.4% efficiency. These efficiency numbers are 2-4 times higher than those of recently reported 300-GHz SiGe or CMOS sources based on multipliers or free-space power combining.

A Novel Millimeter-Wave Dual-Fed Phased Array for Beam Steering

A novel beam-steering approach is presented based on the superposition of two squinted antenna beams. The two antenna beams are realized by exciting the opposite feeds of a dual-fed array antenna. A change in phase difference and amplitude ratio between the input signals, possibly using only one phase shifter and one variable gain amplifier, steers the main beam in different directions. Additionally, sum and difference patterns can be obtained using this concept, allowing for a monopulse operation with a broad peak or a deep null at broadside. Using this approach, beam nulls can also be steered toward interference directions, while keeping the shape and direction of the main beam unchanged. To verify the concept, a 77-GHz demonstrator using a linear patch array antenna and monolithic microwave integrated circuit in-phase/quadrature modulators has been designed and fabricated. The measurement results show a beam-scanning range of 16 °, well in accord with the simulation results.

Compact Topside Millimeter-Wave Waveguide-to-Microstrip Transitions

This letter presents two different waveguide-to-microstrip transition designs for the 76-81 GHz frequency band. Both transitions are fabricated on a grounded single layer substrate using a standard printed circuit board (PCB) fabrication process. A coplanar patch antenna and a feed technique at the non-radiating edge are used for the impedance transformation. In the first design, a conventional WR-10 waveguide is connected. In the second design, a WR-10 waveguide flange with an additional inductive waveguide iris is employed to improve the bandwidth. Both designs were developed for the integration of multi-channel array systems allowing an element spacing of λ0/2 or less. Measurement results of the first transition without the iris show a bandwidth of 8.5 GHz (11%) for 10 dB return loss and a minimum insertion loss (IL) of 0.35 dB. The transition using the iris increases the bandwidth to 12 GHz (15%) for 10 dB return loss and shows a minimum insertion loss of 0.6 dB at 77 GHz.

An Integrated 122-GHz Antenna Array With Wire Bond Compensation for SMT Radar Sensors

This paper shows the antenna design of an integrated 122-GHz radar sensor. The sensor consists of a SiGe IC with a complete radar circuit and two antennas for transmitting and receiving the 122-GHz signal. The IC and the antennas are integrated into a low-cost plastic package that is assembled using wire bond technology. The antenna design was specifically optimized regarding the integration into the package and the compensation of the parasitic effects of the wire bond interconnect. First, the antenna design and its novel feeding technique based on a GCPW transmission line are explained. Then, measurement results including the wire bond interconnect are presented. Finally, details of the complete radar sensor are given.

S-parameter characterization of mm-wave IMPATT oscillators

Designing oscillators in a fully monolithically integrated technology requires accurate characterization of the active element, as well as the surrounding passive circuitry. Based upon S parameter measurements of Impatt diodes, millimeter wave oscillators up to 124 GHz have been designed,manufactured and measured. Two measurements setups covering the frequency range from 0.04-140 GHz were used and a careful calibration approach was applied

Feasibility of automotive radar at frequencies beyond 100 GHz

Radar sensors are used widely in modern driver assistance systems. Available sensors nowadays often operate in the 77 GHz band and can accurately provide distance, velocity, and angle information about remote objects. Increasing the operation frequency allows improving the angular resolution and accuracy. In this paper, the technical feasibility to move the operation frequency beyond 100 GHz is discussed, by investigating dielectric properties of radome materials, the attenuation of rain and atmosphere, radar cross-section behavior, active circuits technology, and frequency regulation issues. Moreover, a miniaturized antenna at 150 GHz is presented to demonstrate the possibilities of high-resolution radar for cars.

Silicon-based radar and imaging sensors operating above 120 GHz

This paper reviews the design considerations, integration issues, packaging and experimental performance of two, recently developed D-Band transceivers with on-die or above-IC antennas fabricated in a production SiGe BiCMOS technology. Potential solutions for future high-efficiency D- and G-Band radio and sensor transceivers are also investigated.

Driving towards 2020: Automotive radar technology trends

In the last few years automotive radar has been transformed from being a niche sensor to becoming standard even in middle-class cars. With Euro-NCAP ratings now requiring automated braking and pedestrian safety functionality, radar is often identified as the best suited sensor for this purpose. Additionally, future automated driving will require detailed and highly reliable information on the environment and surrounding street traffic. This requires radar sensors to provide more detailed information about the environment, foremost in the spatial domain. Automotive radar has always benefited significantly from technological advances, especially in semiconductor technology and packaging, allowing a better performance and much more functionality in the radar frontend. A second key area is the antenna system, where new concepts to acquire more information about signals reflected from the environment can significantly improve resolution and detection performance.