Christian Bredendiek

High-Precision D-Band FMCW-Radar Sensor Based on a Wideband SiGe-Transceiver MMIC

In this paper, a miniaturized D-band frequency-modulated continuous-wave (FMCW) radar sensor with 48-GHz bandwidth (32.8%, 122-170 GHz) and a high measurement rate of > 1 kHz for multi-target vibration measurements is presented. The sensor is based on a SiGe transceiver monolithic microwave integrated circuit manufactured via Infineons B7HF200 bipolar production technology with an fT of 170 GHz and fmax of 250 GHz. Gilbert cell, push-pull, and varactor-based doubler concepts on manufactured chips are compared, and the most promising signal source is embedded into a transceiver chip, which forms the main component of the presented radar sensor. The maximum output power of the system is ≈ -10 dBm and a phase noise of ≈ -80 dBc/Hz is achieved. Measurements are provided to demonstrate the sensor characteristics and show the promising results of FMCW radar in highest precision distance and multi-target vibration measurement applications. Due to the covered wide bandwidth, a range resolution of 5.88 mm is achieved ( -6-dB width, Tukey window). The sensors distance measurement repeatability is 290 nm (65 nm with 10 × averaging and 0.5-m target distance), and the distance measurement accuracy is m for a target in 65-cm distance moving 1 cm. Additionally, vibration measurement results and range-Doppler plots for advanced multi-target applications are presented.

A 240 GHz ultra-wideband FMCW radar system with on-chip antennas for high resolution radar imaging

Nowadays emerging industrial radar applications demand for high-resolution, high-precision and at the same time low-cost radar sensors. Recent advances in semiconductor technology allow highly integrated radar sensors at frequencies up to several hundred GHz in mass-production suitable and cost-effective SiGe bipolar technologies. In this contribution, a SiGe MMIC-based 240 GHz radar sensor with more than 60GHz bandwidth is presented. It consists of a MMIC chip including the high-frequency components and a digital control module with the PLL stabilisation, ramp generation, and data acquisition. The antenna is realized by on-chip patch antennas, which are focused by using an additional dielectric lens. The radar allows fast and highly linear frequency sweeps from 204 GHz to 265 GHz with an maximum output power of ≈ -1dBm EIRP (patch only). A phase noise of <;-65 dBc/Hz (>1 kHz offset) is achieved over the complete tuning range. Additionally range profile, jitter and imaging measurements are presented to demonstrate the achieved system performance.

A 240 GHz single-chip radar transceiver in a SiGe bipolar technology with on-chip antennas and ultra-wide tuning range

This paper presents an ultra-wideband single-chip radar transceiver MMIC around 240 GHz in a SiGe:C bipolar laboratory technology with an fT of 240 GHz and fmax of 380 GHz. The presented transceiver architecture consists of a fundamental 120 GHz VCO, two 240 GHz frequency doublers, a fundamental 240 GHz down-conversion mixer, a divide-by-four stage, a PLL-mixer and two on-chip patch antennas. The complete transceiver architecture is fully differential. The chip facilitates a -1 dBm peak output power (EIRP) at the transmit patch antenna and a tuning range of 61 GHz. The phase noise at 1 MHz offset is -84 dBc/Hz at 240 GHz (and better than -76 dBc/Hz over the full tuning range). The 240 GHz mixer offers a simulated noise figure below 17 dB, a simulated conversion gain of better than 5 dB, and an input refered compression point of -1.3 dBm. The results are achieved with a power consumption of 750 mW from a single 5 V supply.

Differential signal source chips at 150 GHz and 220 GHz in SiGe bipolar technologies based on Gilbert-Cell frequency doublers

This paper presents two differential signal source chips for 150 GHz and 220 GHz in SiGe:C bipolar technologies. The presented architectures consist of a fundamental VCO with a frequency doubling output stage based on the differential Gilbert-Cell. The 150 GHz chip is fabricated in a production technology with an fT of 170 GHz and fmax of 250 GHz, the 220 GHz in an advanced laboratory technology with fT/fmax = 240 GHz/380 GHz. The main goal of this work is to achieve signal sources near the cut-off frequencies of the used technologies with differential outputs. The signal sources achieve a relative 3 dB bandwidth of >; 20% with an output power of 0 dBm and -6 dBm for the 150 GHz chip and 220 GHz chip, respectively. The power consumptions are kept at a moderate level with 430 mW for the 150 GHz chip and 580 mW for the 220 GHz chip from a 5 V supply.

An ultra-wideband D-Band signal source chip using a fundamental VCO with frequency doubler in a SiGe bipolar technology

This paper presents an ultra-wideband signal source chip for the D-Band in a SiGe:C bipolar production technology with an fT of 170 GHz and fmax of 250 GHz. The presented architecture consists of a fundamental VCO with a frequency doubling output stage. The goal of this work is to achieve a signal source near the technologies cut-off frequency while providing good performance concerning phase noise, bandwidth, and output power simultaneously. The chip facilitates a 3 dBm peak output power and a 3 dB bandwidth of 39 GHz. The phase noise at 1 MHz offset is -93 dBc/Hz at 147 GHz (and better than -89 dBc/Hz in a wide frequency range of 39 GHz). The results are achieved with a power consumption of 410 mW from a 5 V supply.

Improvements in distance measurement and SAR-imaging applications by using ultra-high resolution mm-wave FMCW radar systems

Due to advances in technology, resulting in coverage of even higher, and rarely used, frequency regions with low-cost semiconductors, ultra wideband radar systems are getting more feasible for several kinds of applications. In this contribution, the effects of using radar systems with an ultra high spatial resolution, in combination with high precision distance measurements, especially for solid bulk material, and short range synthetic aperture radar (SAR) imaging are discussed. Furthermore, measurements with a wideband (24.5GHz bandwidth) radar sensor in these applications have been done to demonstrate the advantages, of the high resolution. Especially distance measurement applications with many targets or disturbing scatterers benefit from the wide bandwidth. Here, for the measured scenario an accuracy enhancement of a factor 4 to 8 has been obtained by increasing the bandwidth from 4GHz to 24.5 GHz. Furthermore, short range SAR images with a nearly isotropic resolution of 1.3 cm in range, and 1.5 cm in azimuth direction (−6 dB width, Hanning window) are presented. The use of 24.5 GHz bandwidth, and the accordingly better range resolution, which is now in the same dimension as the azimuth resolution, drastically increases the image quality compared to images taken with 4 GHz bandwidth.

A compact, energy-efficient 240 GHz FMCW radar sensor with high modulation bandwidth

In this paper a highly integrated and compactly built FMCW radar system working at a center frequency of up to 240 GHz is presented. With an ultra wide tuning range of 40 GHz a range resolution down to 3.75 mm based on a -6 dB width of the target peak can be achieved, which enables this radar system for various high precision distance measurement and high resolution imaging applications. With the use of a highly integrated system architecture and on-chip antennas based on a single MMIC in combination with a PTFE lens antenna system, a very robust and compact realization is possible. Due to the full integration of all high frequency components, an open cavity QFN package can be used to mount the MMIC on a cost effective and easy-to-fabricate FR4 substrate, which also allows for quick and easy rework processes or chip replacements. The low power consumption of 3.5 W at a supply voltage of 5 V in addition to the compact, cost effective realization and the high resolution make this radar suitable for industrial applications.

SiGe-MMIC based D-Band radar for accurate FMCW multi-target vibration measurements

In this paper a wideband D-Band radar for high precision multi-target vibration measurements is presented. The system is based on a PLL stabilized SiGe MMIC with two VCOs for highly linear fractional-N FMCW sweep generation from 122 to 170 GHz and ≈1ms ramp duration. To demonstrate the capabilities of the FMCW radar, first measurement results are presented. Due to the ultra-wide bandwidth of 48 GHz (≈33%) and the resulting range resolution of 6.04mm (-6 dB width, Hanning window), target separation is even possible in very dense multi-target environments. In freespace measurements with a target in 1 meter distance to the antenna and a SNR of ≈50 dB a distance standard deviation of better than 10 μm is achieved. The combination of phase and peak-center algorithms allow vibration measurements even for fast and large amplitude oscillations. In addition range doppler plots are presented for advanced high precision movement analysis in multi-target environments.

A 24 GHz wideband monostatic FMCW radar system based on a single-channel SiGe bipolar transceiver chip

In this paper a monostatic frequency-modulated continuous-wave (FMCW) radar system around a center frequency of 24 GHz with a wide tuning range of 8 GHz (≈33%) is presented. It is based on a fully integrated single-channel SiGe transceiver chip. The chip architecture consists of a fundamental VCO, a receive mixer, a divider chain, and coupling/matching networks. All circuits, except for the divider, are designed with the extensive use of on-chip monolithic integrated spiral inductors. The chip is fabricated in a SiGe bipolar production technology which offers an fT of 170 GHz and fmax of 250 GHz. The phase noise at 1 MHz offset is better than2100 dBc/Hz over the full-tuning range of 8 GHz and a phase noise of better than 2111 dBc/Hz is achieved at 27 GHz. The peak output power of the chip is 21 dBm while the receive mixer offers a 1 dBm input referred compression point to keep it from being saturated. The chip has a power consumption of 245 mW and uses an area of 1.51 mm. The FMCW radar system achieves a power consumption below 1.6 W. Owing to the high stability of the sensor, high accuracy mesaurements with a range error ,+250 mm were achieved. The standard deviation between repeated measurements of the same target is 0.6 mm and the spatial resolution is 28 mm.

Comparison of inductor types for phase noise optimized oscillators in SiGe at 34 GHz

In this paper two integrated auxiliary VCOs working at a center frequency of 34 GHz for use in a 240 GHz transceiver chip in SiGe technology for ultra-wideband radar applications are presented. The oscillators are using different realizations of the resonator inductance which are compared in terms of quality factor and their influence on the phase noise of the resulting oscillator output signal. The improvement in quality factor at a frequency of 34 GHz between the oscillator using microstrip transmission lines and the oscillator using spiral inductors is simulated to be around 76 % which causes a simulated absolute improvement in output signal phase noise of around 4.5 dB. Both oscillators are realized as test circuits with which the difference can be measured to be around 5 dB proving the advantage of spiral inductors in terms of quality factor for frequencies around 34 GHz resulting in an integrated VCO design providing a low phase noise of -107 dBc/Hz @ 1 MHz offset and a wide tuning range of 6.78 GHz.