Konstantin Statnikov

A Fully Integrated 240-GHz Direct-Conversion Quadrature Transmitter and Receiver Chipset in SiGe Technology

This paper presents a fully integrated direct-conversion quadrature transmitter and receiver chipset at 240 GHz. It is implemented in a 0.13-μm SiGe bipolar-CMOS technology. A wideband frequency multiplier (×16) based local-oscillator (LO) signal source and a wideband on-chip antenna designed to be used with an external replaceable silicon lens makes this chipset suited for applications requiring fixed and tunable LO. The chipset is packaged in a low-cost FR4 printed circuit board resulting in a complete solution with compact form-factor. At 236 GHz, the effective-isotropic-radiated-power is 21.86 dBm and the minimum single-sideband noise figure is 15 dB. The usable RF bandwidth for this chipset is 65 GHz and the 6-dB bandwidth is 17 GHz. At the system level, we demonstrate a high data-rate communication system where an external modem is operated in its two IF-bandwidth modes (250 MHz and 1 GHz). For the quadrature phase-shift keying modulation scheme, the measured data rate is 2.73 Gb/s (modem 1-GHz IF) with bit-error rate of 10-9 for a 15-cm link. The estimated data rate over the 17-GHz RF bandwidth is, hence, 23.025 Gb/s. Also, higher order modulation schemes like 16 quadrature amplitude modulation (QAM) with a data rate of 0.677 Gb/s and 64-QAM with a data rate of 1.0154 Gb/s (modem 250-MHz IF) is demonstrated. A second application demonstrator is presented where the wide tunable RF bandwidth of the chipset is used for material characterization. It is used to characterize an FR4 material (DE104) over the 215-260-GHz range.

160-GHz to 1-THz Multi-Color Active Imaging With a Lens-Coupled SiGe HBT Chip-Set

This paper presents the concept and implementation of an active all-electronic terahertz multi-color imager with the functionality demonstrated in the frequency range of 160 GHz-1 THz. The proposed terahertz system is realized in the form of two independent highly integrated low-cost transmitter (Tx) and receiver (Rx) modules. Each module consists of a single silicon die with a silicon lens-coupled ultra-wideband on-chip antenna and is assembled onto a low-cost FR-4 printed circuit board using traditional wire-bonding. The chip-set is implemented in a 0.25 μm SiGe HBT BiCMOS process with fT/fmax of 280/435 GHz. The main Tx path is composed of an antenna-coupled harmonic generator and is driven by a × 9 multiplier chain fed from an external reference signal centered around 17-18 GHz. Four identical Tx paths are spatially combined on a single chip to increase the output power. The Rx chip shows a 2 × 2 arrangement of identical antenna-coupled broadband sub-harmonic mixers driven by a single × 9 multiplier chain; similar to that from the Tx circuit. The system operates simultaneously at six harmonics being multiple numbers of 165 GHz. The signal-to-noise ratio in transmission-mode active imaging with a 1-Hz resolution bandwidth is 90 dB for 165-GHz band, 115 dB for 330- and 495-GHz bands, 95 dB for 660- and 820-GHz bands, and 70 dB for 990-GHz band.

A 0.32 THz FMCW radar system based on low-cost lens-integrated SiGe HBT front-ends

This paper presents a 0.32 THz high-resolution radar system for short-range applications. It utilizes a homodyne FMCW radar architecture based on a low-cost SiGe HBT chip-set. It is implemented in a 0.13-μm SiGe engineering technology version with cutoff frequencies fT /fmax of 300/350 GHz and offers lens-integrated on-chip antennas. The measured maximum radiated power of the packaged transmitter is -5 dBm (14 dBm EIRP) at 0.311 THz. The 6-dB operational bandwidth of the chip-set is 27 GHz around the center frequency of 0.325 THz. The conversion gain of the receiver including antenna efficiency is -16 to -8 dB and its noise figure is 30-37 dB over the operational bandwidth. The FMCW radar functionality is demonstrated in a face-to-face chip-set configuration.

A wideband 240 GHz lens-integrated circularly polarized on-chip annular slot antenna for a FMCW radar transceiver module in SiGe technology

This paper reports on the design of a broadband lens-integrated differentially-driven circularly polarized annular slot on-chip antenna for a 240 GHz homodyne monostatic FMCW transceiver in a SiGe HBT technology. A complete antenna layout consists of the main radiating annular slot fed by a wideband differential quadrature coupler. The slot is excited by 2 pairs of orthogonal sectorial patch probes located 90° apart along the slot circumference, whereby the mutual coupling between them is exploited to extend the antenna operation bandwidth. The circularly-polarized antenna was simulated to provide an input match superior to -25 dB for 180-310 GHz with consistent radiation patterns. The antenna allows a frequency-unlimited high-efficiency operation of the FMCW transceiver module with a Tx/Rx isolation below -22 dB for 180-310 GHz, a peak radiated power of 4 dBm and in excess of -10 dBm for 214-268 GHz.

A 240-GHz circularly polarized FMCW radar based on a SiGe transceiver with a lens-coupled on-chip antenna

A 240-GHz monostatic circular polarized SiGe frequency-modulated continuous wave radar system based on a transceiver chip with a single on-chip antenna is presented. The radar transceiver front-end is implemented in a low-cost 0.13 µm SiGe HBT technology version with cut-off frequencies f T /f max of 300/450 GHz. The transmit block comprises a wideband ×16 frequency multiplier chain, a three-stage PA, while the receive block consists of a low-noise amplifier, a fundamental quadrature down-conversion mixer, and a three-stage PA to drive the mixer. A differential branch-line coupler and a differential dual-polarized on-chip antenna are added on-chip to realize a fully integrated radar transceiver. All building blocks are implemented fully differential. The use of a single antenna in the circular polarized radar transceiver leads to compact size and high sensitivity. The measured peak-radiated power from the Si-lens equipped radar module is +11 dBm (equivalent isotropically radiated power) at 246 GHz and noise figure is 21 dB. The characterization bandwidth of the radar transceiver is 60 GHz around the center frequency of 240 GHz, and the simulated Tx-to-Rx leakage is below −20 dB from 230 to 260 GHz. After system calibration the resolution of the system to distinguish between two targets at different distance of 3.65 mm is achieved, which is only 21% above the theoretical limit.

A 210–270-GHz Circularly Polarized FMCW Radar With a Single-Lens-Coupled SiGe HBT Chip

A complete circularly polarized 210-270-GHz frequency-modulated continuous-wave radar with a monostatic homodyne architecture is presented. It consists of a highly integrated radio-frequency transceiver module, an in-house developed linear-frequency chirp generator, and a data acquisition chain. The radar front end featuring a fundamentally operated ×16 multiplier-chain architecture is realized as a single chip in 0.13-μm SiGe heterojunction bipolar transistor technology with a lens-coupled circularly polarized on-chip antenna and wire-bonded on a low-cost printed circuit board. In combination with a 9-mm-diameter silicon lens, the module achieves an average in-band directivity of 26.6 dB. The measured peak radiated power from the packaged radar module is +5 dBm and the noise figure is 21 dB. For a 60-GHz frequency sweep, the radar achieves a range resolution of 2.57 mm after calibration, which is close to the theoretical bandwidth-limited resolution of 2.5 mm. With a simple scanning optical setup, this paper further demonstrates the 3-D imaging capability of the radar for detection of hidden objects with a remarkable dynamic range of around 50 dB.

Numerical Computation of Temperature Elevation in Human Skin Due to Electromagnetic Exposure in the THz Frequency Range

The ongoing development of new applications in the terahertz (THz) frequency range, such as wireless communication systems, full-body scanners, or other imaging procedures for biological and medical techniques, rapidly increases the number of persons who are potentially exposed to the electromagnetic radiation of those devices. Studies of thermal effects in humans caused by electromagnetic (EM) exposure with frequencies in the THz frequency range can rarely be found in the literature. In this paper, a method for the numerical computation of a potential thermal response in human skin due to EM fields between 0.1 and 10 THz is introduced. The method starts with the development of adequate simulation models for EM fields with penetration depths less than 1 mm. In a further step, it covers the provision of absolutely needed dielectric tissue parameters with help of the “effective medium theory,” since material properties above 100 GHz are not listed in the commonly consulted databases. The absorbed power in EM exposed human skin models of different complexity is calculated and subsequently used as heat source for temperature simulations. Spatial and time-dependent temperature profiles in the tissue are analyzed for transient and continuous exposures.

A 2×2 lens-integrated on-chip antenna system for a 820 GHz multiplier-chain source in SiGe technology

This paper reports on the design of a compact wire ring on-chip antenna system for a spatial power combining single-chip transmitter at 820 GHz implemented in 0.25μm SiGe HBT technology. The array with a 2×2 arrangement illuminating a hyper-hemispherical silicon lens through the chip backside is driven by 4 parallel on-chip multiplier chains and is capable of delivering a single Gaussian-like beam without any external phase/amplitude tapering applied externally to the antenna inputs. When assembled with a 4-mm diameter lens without matching cap, the source delivers around 1.9 μW output power and shows a directivity of 26 dBi. The operation bandwidth is around 800-840 GHz.

A lens-integrated on-chip circular slot antenna for a 240 GHz power source in SiGe technology

This paper reports on the design of a broadband lens-integrated differentially-driven circular slot on-chip antenna for a 240 GHz power source implemented in a SiGe HBT technology. The circular slot is excited by 2 sectorial patch probes located in the antenna aperture, whereby the mutual coupling between them is exploited to extend the antenna operation bandwidth in the lower range of the operation frequency. The antenna allows a frequency-unlimited operation of the multiplier-chain based power source with a peak radiated power of at least 1.18mW at 250 GHz and in excess of 100μW for 222-276 GHz.

Towards 3D-imaging with low-cost SiGe-Technology at 160GHz

This paper presents a compact, low-weight and flexible continuous wave (CW) millimeter-wave (mmWave) active imaging system implemented in low-cost SiGe-Technology. It is based on a receiver (RX) chip with zero-intermediate frequency (IF) quadrature mixing covering the 158-to-165 GHz band. This heterodyne imaging system provides dynamic range of 110 dB and yields high imaging contrast. Using this mmWave imaging system it is possible to exploit both the magnitude and the phase information of the transmitted wave. The available bandwidth of 8 GHz can be employed for swept sources in radar sensing applications offering the capability of 3D image reconstruction.