A compact antenna setup, that can be used for e.g. radar applications, will be presented in this paper. The antenna is formed by an antipodal Vivaldi design on a 50 μm thin liquid crystal polymer (LCP) substrate. The feeding line is designed as grounded coplanar waveguide (GCPW). In the direction of radiation, the antenna is followed by a dielectric cone of high-density polyethylene (HDPE), whereby the front of the cone terminates in a radial lens shape for beamforming purposes. The presented setup is designed and built for W-band (75 to 110 GHz) operation, the concept itself can also be used for any other frequency range. Performance measurements, as well as comparisons with previous simulation results will be presented.

Places which have to be monitored permanently (such as security sectors, industrial areas or power plants) are facing the problem of large-area monitoring. Optical security cameras can observe such areas under good lighting and visibility conditions, but objects might get invisible when fog, darkness or smoke reduces the visibility. This problem can be solved with millimeter-wave radars with very high slew rates of the chirp signal. The radar has a detection range of above 100 m and can determine the distance and speed of objects inside the observation area very precisely. For most applications, the position of objects is more important than their color or size.

Sub-millimetre wave or terahertz heterodyne receivers operating above 300 GHz are key instruments for many space applications. For example, they are required for monitoring of the earth’s atmosphere or for detection of molecules that are important for the chemistry other planet’s atmospheres, for example water vapour. Meteorological phenomena, which can be studied at these frequencies, are cloud ice water content, ice particle sizes and distribution, which are important parameters for the hydrological cycle of the climate system and the energy budget of the atmosphere. Existing terahertz heterodyne receivers are usually bulky due to complex local oscillator (LO) chains. In a joint effort (project “TeraComp”) [1], we have developed a compact and efficient 557-GHz heterodyne receiver front-end with low power consumption and low noise temperature by minimizing the number of components, through integration, in the LO chain. The front-end consists of a low noise subharmonic Schottky diode membrane mixer, a 275 GHz Heterostructure Barrier Varactor frequency tripler, a 92 GHz mHEMT power amplifiers and a 15 to 92 GHz 6x multiplier as part of the LO chain. The receiver covers the frequency band from 515 to 600 GHz. It has a measured double-sideband noise temperature as low as 1300 K at room temperature, which makes it a sensitive receiver for applications where cryogenic cooling can’t be used. In this paper, the results of the performance tests will be presented. This includes noise temperature measurements across the receiver band, Allan-time stability measurements, and beam pattern measurements. Finally we will present the performance of the receiver when used for molecular spectroscopy of CH3OH with a digital Fast Fourier transform spectrometer as back-end. [1] Terahertz heterodyne receiver components for future European space missions (242424) - www.fp7-teracomp.eu

Here we will present a new design for the vertical waveguide structure of (AlGaIn)(AsSb)-based diode lasers leading to a reduced beam divergence in the fast axis of only 44° full width at half maximum (FWHM), compared to 67° FWHM of a standard broad waveguide design. Uncoated ridge-waveguide diode lasers emitting at 2.3 μm with a 1000×64 μm2 geometry showed a threshold current density of 180 A/cm2 (or 60 A/cm2 per QW), which is among the lowest values, reported for GaSb-based diode lasers.

A large amount of bandwidth has been achieved with advanced construction methods developed for ultra-high bandwidth distributed amplifiers. A 66 GHz-bandwidth GaAs device with more than 6 Vpp of voltage swing has been manufactured.

Due to the poor thermal conductivity of GaAs, successful power amplifier design in coplanar technology requires careful thermal considerations. The influences of the active device geometry and mounting conditions have been investigated theoretically and experimentally to provide reliable thermal management design data. 50-µm thinning and flip-chip with thermal bump attachment on AlN or diamond exhibited temperature rises in the order of 50 and 40-30 °C respectively, leading to significant improvement in the performance of coplanar power devices and circuits. These results demonstrate the potential of coplanar MMIC technology for high power applications.

A modulator driver has been developed for use in 40 Gbit/s optical transmission systems. It is a two-stage device with distributed amplifiers in the stages, which is monolithically integrated on a single chip with a high gain of 20 dB, high output voltage swing of 5 V and ultraboadband operation with a bandwidth of 46 GHz.

Two 38/76 GHz push-push frequency doublers have been realized in a 0.15 μm GaAs PHEMT technology. The circuits are based on different 180/spl deg/ power divider structures: a Lange coupler followed by a 90/spl deg/ transmission line, and a balun. The circuits achieve maximum conversion gains of -4 and -6 dB for 12 and 14 dBm input signals, respectively. The fundamental suppression is approximately 30 dBc in both cases. To our knowledge, these results represent the best performance reported to date for W-band balanced doublers.

Two compact coplanar MMIC amplifiers having high output power at Ka-band are presented. Based on our 0.15-/spl mu/m GaAs PHEMT process on 4" wafers, a two-stage MMIC driver amplifier has demonstrated at 35 GHz, a linear gain of 11 dB, an output power at 1 dB gain compression P/sub -1dB/ of 350 mW, and a saturated output power P/sub sat/ greater than 500 mW. At the same frequency, the coplanar high power amplifier achieved a linear gain of 9.5 dB, with P/sub -1dB/=725 mW and more than 1 Watt of saturated output power. To our knowledge, this is the highest output power ever reported at Ka-band for any coplanar MMICs.

This letter presents an optimized single-stage MMIC tripler with W-band output frequency (76.5 GHz). The circuit is based on an 0.15 μm gate-length AlGaAs/InGaAs/GaAs PHEMT. By using a class AB transistor bias point and carefully selecting its input and output terminations, a high conversion gain of -4.3 dB for an 8.5 dBm input signal and a saturated output power of 7 dBm have been obtained. To our knowledge, these results represent the best performance reported up to date for an active frequency tripler with W-band output frequency.

40 Gbit/s 1.55 /spl mu/m photoreceivers were manufactured using GaAs-based HEMT distributed amplifiers. The photoreceivers include either a integrated surface-illuminated PIN or a flip-chip mounted edge-illuminated multimode waveguide photodiode.

The threshold voltage of PHEMTs fabricated by a selective dry etched gate recess using fluorine containing plasma, is higher than expected from calculations. An increase in dry etch time increases the threshold voltage. The recess depth is hardly effected by the etch time, because the dry etching stops on AlGaAs by forming non volatile AlF3.We investigated MBE grown doped GaAs layers and HEMT structures after fluorine plasma treatment and different post dry etch dips, before and after annealing. A drastic increase in sheet resistance of these layers was observed. SIMS depth profiling identified fluorine at the surface, fluorine diffusion into silicon doped GaAs, fluorine accumulation at the GaAs/AlGaAs interface and at the silicon pulse doping. We conclude, that the observed positive shift in threshold voltage is due to compensation of silicon donors, acceptor states or electron traps caused by fluorine.

A two-stage D-band amplifier MMIC with 12 dB gain at 148 GHz has been developed, using a 0.15 /spl mu/m AlGaAs/InGaAs/GaAs PHEMT technology. The amplifier employs cascode HEMT devices with 2/spl times/30 /spl mu/m gate periphery, having a maximum oscillation frequency f/sub max/ of 180 GHz. On-wafer vector measurements up to 200 GHz were performed, using active probes based on nonlinear transmission lines. The circuit features coplanar technology for compact size and low cost. The overall chip-size is 1/spl times/1.5 mm/sup 2/.

We report the design and fabrication of compact 2- and 3-stage coplanar (CPW) microwave monolithic integrated circuit (MMIC) amplifiers having high output power at Ka-band. Based on a 0.15-μm gate length GaAs PHEMT process, a two-stage MMIC driver amplifier has demonstrated at 35 GHz, a linear gain of 11 dB, an output power at 1 dB gain compression P/sub -1 dB/ of 350 mW, and a saturated output power P/sub sat/ greater than 500 mW. For the same frequency, the high-power CPW 2-stage amplifier achieved a linear gain of 9.5 dB, with P/sub -1 dB/=725 mW and more than 1 W of saturated output power, Additional thermal management resulted in an increased performance, namely, 10.4 dB linear gain, P/sub -1 dB/=950 mW and P/sub sat/=1.2 W. To our knowledge, these are the highest output powers ever reported at Ka-band for any uniplanar MMIC.

High performance single pole double throw (SPDT) and single pole triple throw (SPTT) switches optimized for center frequencies of 94 GHz and 77 GHz, were realized in coplanar waveguide GaAs MMIC technology using resonated PIN diodes. SPDT switches are shown with 1.3 dB (<1.6 dB) insertion loss and 22 dB (>21 dB) isolation at 94 GHz (entire W-Band). SPTT switches achieve 2 dB (1.8 dB) insertion loss and 38 dB (40 dB) isolation at 94 GHz (77 GHz).

An IC technique for clock recovery and frequency multiplication was developed by combining a preprocessor, an injection-synchronised narrowband ring voltage controlled oscillator, and a phaselocked loop. A 40Gbits/GHz IC was realised using 0.2 mu m GaAs HEMTs. A multiplying factor as high as 64 was reached. The DC consumption is 900mW.

A coplanar subharmonic injection locked W-band HEMT VCO with an integrated varactor diode and buffer amplifier was developed, achieving a tuning range of 10 GHz and an output power of 8 dBm at 94 GHz. The oscillator was stabilized by subharmonic injection locking to reduce phase noise and simultaneously by an external phase-locked-loop (PLL) circuit to compensate for temperature drift. The locking range of the system was extended to 1 GHz by the use of the PLL circuit.

A high speed modulator driver has been developed and realised using GaAs P-HEMT technology. The driver is realised as a distributed amplifier and gives an output signal with a voltage swing of >5 V at a data rate of 40 Gbit/s.

For 76-GHz transmitters, two coplanar monolithic microwave integrated circuit (MMIC) frequency multipliers were realized in a 0.15-μm pHEMT technology on GaAs. A 38/76-GHz frequency doubler achieved a state-of-the-art output power of 10 dBm for a 16-dBm input signal and a maximum conversion gain of -4 dB. For a 19/76-GHz frequency quadrupler, a high conversion gain of -7.5 dB for an input power of 8 dBm and a saturated power of 4 dBm was demonstrated. To our knowledge, this is the first reported W-band one-stage frequency quadrupler based on HEMT technology.