This article demonstrates a fully integrated broadband four-channel phased array transceiver, capable of wireless data rates up to 200 Gb/s covering the entire $D$ -band (110–170 GHz). The circuit is developed in a 130-nm SiGe BiCMOS technology, featuring ${f}~_{\text {t}}/{f}~_{\text {max}}$ of 300/500 GHz, and includes localized back-side etching-based ON-chip patch antennas. In both transmit and receive modes, direct up- and down-conversions are performed by in-phase and quadrature mixers driven by a multiplier-by-four local oscillator chain. A bidirectional true time delay circuit, with a resolution of 0.446 ps, which is equivalent to the accuracy of a 4-bit phase shifter, provides the squint-free beam-steering capability. Beam-steering measurements show how the beam can be steered from −45° to 45° in a 7° step. The transceiver achieves a 3-dB baseband bandwidth of 30 and 27 GHz in the transmit and receive modes, respectively. A wireless link demonstration is performed by mounting two chips on printed circuit boards, one in the transmit and one in the receive mode, together with plastic lenses on both sides, at a distance of 15 cm. Hardware-in-the-loop measurements show record data rates of 180 Gb/s with EVM of 12.2% using 16-QAM and 200 Gb/s with 8.3% EVM using 32-QAM. The four-channel transceiver consumes 1.95 and 2.5 W in the receive and transmit modes, respectively, which correspond to power efficiencies of 9.75 pJ/bit in the receiver mode and 12.5 pJ/bit in the transmitter mode.

This article proposes a fully integrated single-channel bistatic frequency-modulated continuous-wave (FMCW) radar transceiver (TRX) that operates at a center frequency of 256 GHz. The main focus of this work is to realize a wideband and efficient radar TRX that offers high resolution of target detection in the short-range FMCW radar sensing application. The radar TRX chip is designed and manufactured using the 130 nm silicon–germanium (SiGe) bipolar complementary metal-oxide-semiconductor (BiCMOS) technology which offers heterojunction bipolar transistors (HBTs) with $f_{\mathbf {T}}/f_{\mathbf {MAX}}$ of 300/500 GHz. The transmitter (TX) of the radar TRX is based on a fundamentally operated multiplier-by-8 chain architecture that offers a 3-dB bandwidth of around 65 GHz with a saturated output power of −5.4 dBm. On the other hand, the receiver (RX) is based on a subharmonic architecture that provides a conversion gain (CG) of 10.4 dB with an average noise figure (NF) of 23.5 dB. This TRX is realized with two integrated on-chip folded dipole antennas. The antenna offers high antenna gain and radiation efficiency due to the use of the selective localized backside etching (LBE) technique. This chip consumes 305 mW of power from a 3.3-V supply and occupies a silicon area of 3.3 mm2. The radar range measurement is performed in an anechoic chamber, and it shows the maximum dynamic range (DR) of around 34 dB at 1-m range of the target.

This paper demonstrates a 160GHz transceiver (TRX) chip in 130nm BiCMOS technology with localized backside etching (LBE) on-chip antenna array. The Transmitter (TX) is equipped with a vector modulator while the receiver (RX) makes use an in-phase-quadrature (IQ) topology to enable not only multimode radar techniques but also a joint radar-communication (JRC) operation. The chip area is utilized efficiently to synthesize a single $2\times 1$ patch antenna array in a monostatic architecture employing a rat-race coupler which provides 30dB TX-RX isolation in the radar operation mode. Thanks to the silicon LBE capability, the array-on-chip achieves 8.5 dBi. The JRC chip is fabricated and a prototype hardware is manufactured where the effective isotropic radiated power is measured at D-band (110-170GHz) for validation.

Although the word radar is currently widely used as a standard word in our daily lives, it is, indeed, an acronym for “radio detection and ranging” from the 20th century. As early as 1886, German physicist Heinrich Hertz used experiments to prove that radio waves can be reflected from solid objects. In 1904, German engineer Christian Hülsmeyer used radio waves to detect ships in dense fog. The period on the eve of and during World War II was a key time for the rapid development and formation of radar in the modern sense. Continuous wave (CW) and pulse radar, especially the latter, have been widely used until today. Since then, in addition to military radars, which have always been dominant, other applications, such as meteorological radars for weather monitoring and atmospheric research and remote sensing radars for surface and geological imaging, have also been widely used.

This article proposes a planar, wide fan-beam differential, corporate-fed patch antenna array architecture for automotive radar applications that mitigates the multipath and multiple reflections effects of its conventional series-fed counterpart. The proposed array architecture offers the merits of wide beamwidth in azimuth, high gain, yet, is applicable in multiple-input, multiple-output (MIMO) configurations. Two 8 × 1 arrays were developed, built, and measured at the 77-81-GHz band. In design 1, the width of driven 50-Ω patch is optimized for the widest beamwidth and the array feeding network employs impedance transformers for matching. The experimental verification showed an azimuthal half-power beamwidth (HPBW) of 70° with a 15-dBi gain. In design 2, the interelement spacing is increased for wider beamwidth and less mutual coupling, and the feeding network transformers were eliminated to mitigate scattering and radar cross section (RCS) in turn. A 130° azimuthal HPBW was measured. A 2 × 2 MIMO radar hardware was built, employing the proposed array architecture on a scalable radar platform to validate its applicability in MIMO radars. For the sake of comparison, another reference demonstrator with conventional series-fed arrays was built. Frequency-modulated continuous-wave (FMCW) radar range and angle measurements were performed where multiple reflections and multipath effects were mitigated.

This paper proposes a millimeter-wave (mmWave) radar sensor architecture for contactless vital signs detection and monitoring at the industrial, scientific, medical (ISM) 60 GHz band. Such fast remote touchless monitoring is extremely important during pandemic seasons such as COVID-19. The architecture utilizes a leaky wave antenna to synthesize a reconfigurable radar beam whose direction is steered in the space without additional modulator circuits. The modulatorless architecture enables monitoring the vital signs of multiple patients at different locations by measuring the Doppler shifts from their movements. Furthermore, it also offers building power and cost effective sensor components by eliminating the modulator circuitry. The system considerations of the proposed architecture are discussed and the Doppler radar technique for vital signs detection is reviewed. A laboratory experiment of measuring the Doppler shift due to a vibrating target using a prototype of the proposed sensor is successfully conducted. The application of the proposed sensor can be extended to remotely scan and control running machines in industrial environments.

This paper presents a micromachined millimeter-wave stacked patch antenna at D-band for high resolution radar applications. The top most two metal layers in the backend of line of a 130-nm SiGe BiCMOS technology is utilized to feed a main patch loaded by another parasitic patch with a different length in order to widen the bandwidth. The silicon under the antenna is selectively removed to synthesize air trenches to get rid of the poor radiation efficiency in silicon substrates. The simulated radiation pattern exhibits $108^{\circ}$ and $90^{\circ}$ half-power beam widths in the two principal planes with a peak radiation efficiency of 62%. A prototype chip is fabricated to validate the design where the radiation pattern is measured across frequency and the peak effective isotropic radiated power over frequency is compared with a single patch counterpart prototype.

This paper demonstrates the data communication capability of a 79 GHz scalable bistatic radar sensor based on transceiver (TRX) BiCMOS chip. Two TRX chips equipped with binary phase-shift keying (BPSK) modulators together with phase-locked loop (PLL) chip and four 8×1 antenna arrays construct a 2×2 multiple-input multiple-output (MIMO) radar, where the BPSK modulators are utilized either for frequency-division multiplexing (FDM) MIMO operation, or for data communication over radar. A 10 Mbps pseudo random binary sequence (PRBS) modulation of the radar signal is demonstrated where the corresponding received signal was successfully measured at 1 m away receiver with 10 GSps real-time oscilloscope.

This paper demonstrates a sub-cm range resolution of a D-band (110–170 GHz) radar based on a bistatic BiCMOS mmWave IC with on-chip antennas. A wideband ring voltage-controlled oscillator (VCO) is utilized to generate a 20 GHz sweep bandwidth which translates to a frequency-modulated continuous-wave (FMCW) modulation bandwidth of 80 GHz by means of a built-in quadrupler in the radar transceiver chip. A demonstrator board is developed where the FMCW operation is investigated. A ranging precision of 75 µm is verified at 0.5 m without lenses, whereas a 6-dB effective range resolution of 6 mm with Hann window was measured. A calibration against the nonlinearity in the radar output signal due to the very wide bandwidth is discussed. The calibrated range resolution approaches the theoretical limit of 3.8 mm with Hann window.

This paper quantifies the ranging precision of a 79 GHz frequency-modulated continuous wave (FMCW) radar sensor employing typical on-board antenna arrays and off-the-shelf crystal oscillator components. Two radar boards are built using the same transceiver and phase-locked loop chips with external ±25ppm and ±1ppm crystal oscillators. The FMCW ranging precision in each case is measured and compared with that employing a laboratory test equipment as a reference signal. A range accuracy in microns regime is experimentally verified with the employed off-the-shelf crystal oscillators and without additional lens or horn antennas.

This paper demonstrates a millimeter-wave (mm-Wave) radar sensor chip set for industrial, scientific, medical (ISM) and internet of things (IoT) applications. Thanks to their modular expandable wireless transceiver architecture, these radar chips offer implementing multimode radar sensors capable of deploying multiple radar techniques to detect object presence, range, velocity, vibrations and direction of arrival across multiple applications in conjunction with data communication capability for machine-to-machine (M2M) interaction. A 60GHz single-channel radar sensor prototype is implemented where the frequency modulated continuous wave (FMCW) radar technique is applied for object detection and range measurement in a multitarget scenario. A range resolution of 6cm and a ranging precision of 0.lmm at 1m range are experimentally verified. Another two-channel sensor prototype is implemented where multiple-input multiple-output (MIMO) radar technique is applied for direction-of-arrival (DoA) estimation. An experiment of measuring vibration rates from multiple targets at different locations using Doppler radar technique is successfully conducted. This experiment simulates a remote control environment of running machines in factories. Furthermore, an experiment of monitoring a human heartbeat rate remotely by the sensor is performed where a 78bpm rate is measured. Such contactless measurement is extremely important to prevent disease spreading during pandemic seasons such as COVID-19.

In this paper the Nippon Pillar's low-loss substrate material F300AS is utilized to implement a planar single-layer substrate-integrated waveguide (SIW-) based vertical waveguide transitions to cover the full WR12 band. Two designs are implemented on thin and thick substrate to seek the maximum obtainable bandwidth. The SIW-WR12 transition comprises of rectangular aperture and two via pairs to widen its bandwidth. The simulated 1-dB bandwidth spans from 60-88 GHz on the thick substrate. The transition is directly mounted on the board and it does not require additional mechanical parts for fixation. Back-to-back structures were fabricated and measured for verification.

A distance selective pseudo-random noise (PRN)-coded Doppler radar is proposed. The radar is capable of measuring the vital signs of a human in a noisy environment with high precision. The distance selectivity feature is achieved by the use of PRN modulation to focus on the desired target at a certain distance and suppress the Doppler frequencies of other targets at different distances. In addition, an offset signal using Delta–Sigma modulation is generated to cope with the suppression of low-Doppler frequencies, very close to DC, in AC-coupled systems. The authors compare the performance of the proposed radar system to a frequency modulated continuous wave radar in measuring the Doppler frequencies of two loudspeakers located at different ranges. In addition, they experimentally evaluated the proposed radar in measuring the vital signs of a human in a noisy environment. The radar is capable of isolating the Doppler frequencies of the vital signs from the surrounding noise. In addition, vital signs information is preserved at higher frequencies away from the high-pass filter in AC-coupled systems.

A 320 GHz on-chip circularly-polarized (CP) antenna array that has been facilitated with 0.13 μm SiGe BiCMOS technology is presented. It is the first designed and prototyped THz-band on-chip antenna array with circular polarization and high directivity. The antenna is realized by designing a 4 ×4 microstrip-fed CP patch antenna array inside the silicon dioxide layer on top of a silicon base. A sequential phase rotation scheme is applied to the four 2 ×2 subarrays to achieve wide axial ratio (AR) bandwidth (8.7 GHz). The antenna array was successfully prototyped in a 3.6×3.6 mm 2 area on a silicon wafer. Consequently, it easily combined with other integrated circuit (IC) components. The developed THz on-chip CP antenna is highly desired for the emerging ultra-high speed wireless applications.

Modular 80- and 160-GHz 4-channel radar sensor platform is introduced based on relaxed single 40 GHz local oscillator source. The first two channels synthesize 2×2 multiple-input multiple-output (MIMO) radar at 80 GHz with on-board planar 8×1 patch arrays for enhanced angular resolution, while the other 2 channels employ 160 GHz system-on-chip (SoC) transceivers with integrated wideband 6-dBi on-chip antennas with air trenches for enhanced range resolution. Bistatic frequency modulated continuous wave (FMCW) and delta-sigma (Δ∑) modulation based frequency division multiplexing (FDM-) MIMO radar techniques are demonstrated. The flexible architecture of the modular radar platform allows also implementing fast-chirp, Doppler and selective distance radar techniques as well as 2-dimensional (2-D) ranging and data communication over radar imaging.

The dream towards fully autonomous vehicles brings a lot of challenges in terms of reliability, high performance computing and sensing capabilities in a vehicle. Nowadays, autonomous vehicles are equipped with several sensors, which allow the vehicle to sense everything on the road and to collect the information needed to drive safely. Altogether, these sensors generate a lot of data, roughly 4TB in a single day [1]. In order to process this abundance of sensory data faster and reliably, there is a need for high performance microcontroller units (MCUs) and fault tolerant data processing respectively. For this reason, we have developed a smart reconfigurable sensor (SRS) platform, which aims to solve the challenges of high performance computing and safety. An in-house fabricated entire silicon-based millimeter-wave transceiver, using IHP's 130 nm SiGe BiCMOS technology, is used as SRS front-end and software (SW) based triple modular redundancy (TMR) system is implemented for fault tolerant radar data processing. Our highly adaptive system supports fault tolerant modes (i.e. fail operational, fail safe), low power mode and distributed execution of tasks among different cores, all while meeting the strict automotive standards.

This paper presents a millimeter-wave printed Yagi-Uda endfire antenna at 160 GHz for sensing applications. The backend of line (BEOL) of a 130-nm SiGe BiCMOS technology is utilized to feed the Yagi antenna that is printed on the top most metal layer. The silicon under the antenna is removed to synthesize high efficiency endfire radiation pattern while complying with the process rules. The radiation pattern has 92° and 51° half-power beam widths in the two principal planes and -9 dB back-lobe level. The radiation pattern is stable over 10 GHz bandwidth. A prototype chip is fabricated to validate the design where the radiation pattern is measured. Simulations and measurements agree with each other and the measured peak gain is 2 dBi with integrated balun. This developed endfire antenna mitigates the radar cross-section (RCS) of the final sensor.

This article presents $G$ -band monostatic and bistatic radar transceivers (TRX) incorporating on-chip antennas for short-range high-precision applications. The circuits were fabricated using a silicon–germanium (SiGe) BiCMOS technology offering heterojunction bipolar transistors (HBTs) with $\bf {f}_{\mathbf {T}}/\bf {f}_{\mathbf {MAX}}$ of 300/500 GHz. The monostatic TRX implements a tunable leakage canceller (LC) for enhanced transmitter (TX)-to-receiver (RX) leakage compensation and hence improved detectability of weakly reflecting near targets. A standalone monostatic TRX characterized at on-wafer level achieves 4-dBm maximum output power ( $\bf {P}_{\mathbf {TX}}$ ) and 19-dB peak conversion gain ( $\bf {G}_{\mathbf {RX}}$ ) with 3-dB bandwidths of 18 and 17GHz for the TX and the RX, respectively. The bistatic version reaches $\bf {P}_{\mathbf {TX}}$ of 13 dBm and $\bf {G}_{\mathbf {RX}}$ of 24 dB expanding the 3-dB bandwidths to 32 and 34 GHz for the TX and RX, respectively. A double-folded dipole antenna providing 5-dBi gain at 170 GHz was implemented using localized backside etching (LBE) and integrated with the transceivers. A frequency-modulated continuous-wave (FMCW) radar demonstrator incorporating an external phase-locked loop (PLL) was built to evaluate both TRXs and tunable leakage cancellation feature available in the monostatic variant. The maximum equivalent isotropic radiated power ( $\bf {EIRP}$ ), including on-chip antennas, is 8 and 18 dBm for the monostatic and bistatic TRX, respectively. The radars support sweep bandwidth up to 20 GHz reaching 2.1 cm spatial resolution. For a target at 1 m distance the measured ranging precision is $105~\mu \text{m}$ and $13~\mu \text{m}$ for monostatic and bistatic TRX, accordingly. Activation of leakage cancellation effectively suppresses close-in noise and extends the minimum detectable range remarkably.

A wideband 4-way combined power amplifier (PA) in a 0.13-μm BiCMOS process is presented. The overall PA is based on four unit cells of 3-stage cascode PA, which is adopted for larger output power and higher gain. Load pull simulations are done to optimize the unit cells together with the 4-way combiner for wideband characteristics. With the assistance of hicum and vbic models, the overall PA shows a peak gain of 30dB at 126GHz with the 3-dB bandwidth higher than 80GHz. Under large-signal excitation, the PA delivers a maximum output power greater than 17.5dBm at 120-180 GHz with peak PAE higher than 5%. The PA can be used for various future D-band applications. Measurements are on the way and will be presented into the final contribution.

This article demonstrates the implementation of 80and 160-GHz four-channel radar sensors employing the modular scalable platform based on a single relaxed 40-GHz local oscillator and cascadable transceiver chips. The first two channels synthesize 2 × 2 multiple-input-multiple-output (MIMO) radar at 80 GHz with onboard 8 × 1 patch arrays for enhanced angular resolution, whereas the other two channels employ 160-GHz system-on-chip transceivers with integrated wideband 6-dBi micromachined on-chip antennas for enhanced range resolution. Configurable modulators in each transceiver offer ranging, direction-of-arrival (DoA) estimation, velocity/vibrations measurement, and data communication applications. Frequency-modulated continuous wave (FMCW) is demonstrated with 4-/8-GHz sweep bandwidth at 80/160 GHz corresponding to 3.75-/1.875-cm range resolution. Chirp-sequence FMCW is employed to measure the heartbeat rate of a human, and 78 bpm is measured with 0.06-Hz Doppler resolution. Mechanical vibration rate from a loudspeaker is measured using the CW radar technique, whereas phase-modulated continuous wave is employed for distant selective vibrations measurement. Time-division multiplexing MIMO radar is configured at 80 GHz in a multitarget scenario for DoA estimation, and the targets are distinguished with 25° effective angular resolution. Frequency-division multiplexing MIMO radar technique is demonstrated based on ΔΣ-modulation and binary phase shift keying (BPSK) modulators. Furthermore, the 10-Mb/s BPSK data communication link is evaluated at 80 GHz with a 20-dB signal-to-noise ratio at 1 m. The 160-GHz vector modulators offer additional modulations.