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Human Machine Interaction based on air gestures finds an increasing number of applications in consumer electronics. The availability of mmWave technology, combined with machine learning, allows the detection and classification of gestures, avoiding high-resolution LIDAR or video sensors Nevertheless, in most of the existing studies, the processing takes place offline, takes into account only the velocity and distance of the moving arm, and can handle only gestures that are conducted very close to the sensor device, which limits the range of possible applications. Here, we use an experimental multi-channel mmWave- based system that can detect small targets, like a moving arm, up to a few meters away from the sensor. As our pipeline can estimate and take into account the angle of arrival in azimuth and elevation, it has the ability to classify a greater variety of dynamic gestures. Furthermore, the digital signal processing chain we present here, runs in real-time, incorporating an event detector. Whenever an event is detected, a novel empirical feature extraction takes place and a Multi-Layer Perceptron is deployed to infer the type of the gesture. To evaluate our setup and signal processing pipeline, a dataset with ten subjects, performing nine gestures was recorded. Our method yielded 94.3% accuracy on the test set, indicating a successful combination of our proposed sensor and signal processing pipeline for real time applications.

Recent publications have investigated and demonstrated new digital modulation techniques that allow realization of orthogonal frequency division multiplexing (OFDM) radar with relatively low hardware effort. This is especially interesting as the digitally defined signals offer additional freedom for multiplexing schemes of multiple-input multiple-output (MIMO) radar sensors. MIMO radar sensors rely on strictly orthogonal signals to distinguish between multiple transmitters (TX). To span a virtual array with a maximum number of antenna positions, a novel method that combines orthogonal signals with strongly correlated signals generated by space-time coding (STC) is introduced. This leads to virtual transmit antenna positions that are used to improve the unambiguous angular area of an otherwise ambiguous MIMO antenna array. The proposed method is validated with an integrated OFDM radar at millimeter-wave frequencies.

Next-generation radar sensors require imaging capabilities with high angular resolution. As for a single sensor, the aperture, and thus the achievable resolution, is limited due to the constraints of the front end, radar networks consisting of multiple sensors are a possible solution. However, their incoherency usually makes joint angle estimation impossible. This article presents a network concept consisting of an orthogonal frequency-division multiplexing (OFDM) radar and repeater elements, which receive the reflections from targets and retransmit them back to the radar. Thereby, any frequency conversion from radio frequency to baseband and vice versa is omitted such that the signal remains coherent to the initial transmit signal. To distinguish the bistatic signal transmitted by the repeater from the monostatic one of the OFDM radar, the orthogonal subcarrier structure of OFDM waveforms is exploited by combining a sparse radar transmit signal with a low-frequency modulation in the repeater. This allows to evaluate the bistatic signals at the radar with standard multiple-input-multiple-output (MIMO)-OFDM signal processing, leading to separate range-Doppler images for each virtual channel. Finally, it is shown that this method offers a coherent angular estimation based on the extended aperture of the network. For this purpose, a method to establish phase coherency by a reconstruction of the modulation phase is presented. The network concept is proved with measurements at 77 GHz., publishedVersion

Coherent radar-repeater networks offer great opportunities, e.g. in network-based direction of arrival (DoA) estimation. However, due to the special bistatic signal path with two reflections at the targets, the bistatic measurements are affected by additional ghost targets. The de-ghosting algorithm presented in this work not only allows for a mitigation of this additional ghost-targets but also the identification of unwanted clutter peaks. Thus, it enables the efficient exploitation of the network's possibilities, as verified by measurements., acceptedVersion

Radar networks offer the opportunity of enhancing the radar sensing performance beyond the inherent limitations of single multiple-input multiple-output (MIMO) radars. Different locations of the individual sensor nodes allow for diverse observation angles on the targets. Moreover, in case of a coherent network, such as radar-repeater networks, the direction of arrival (DoA) capabilities are increased. However, a crucial point in exploiting the full potential of a sensor network is the separability of the signals originating from the different sensor nodes during operation, while preserving reasonable radar sensing performance of the individual sensors and the network. In this paper multiplexing methods for an orthogonal frequency-division multiplexing (OFDM)-based radar network are proposed and investigated. The first method combines traditional time and frequency multiplexing, while the second method applies a random assignment in combination with a compressed sensing-based signal evaluation. Both methods are compared with the traditional FDM multiplexing for MIMO-OFDM. For this purpose, performance criteria are proposed and the concepts are evaluated based on measurements and simulations., acceptedVersion

Digital modulations such as orthogonal frequency-division multiplexing (OFDM) have received increasing interest for radar. However, the required fast analog-to-digital (AD) and digital-to-analog (DA) converters providing the necessary bandwidth have not been feasible for automotive applications so far. In this paper, the first highly integrated, fully coherent OFDM radar capable of multiple-input multiple-output (MIMO) and stepped-carrier OFDM for automotive applications is presented. The stepped-carrier OFDM approach is adopted to reduce AD/DA requirements using an analog local oscillator (LO) frequency step generator. The capability to generate frequency steps with a duration of a few microseconds required for automotive applications is demonstrated. Calibration steps that are required with the new architecture are discussed and measurements are done to validate the functionality of the system. Also, possibilities for adaptive reconfiguration of the radar sensor in the presence of ambiguities are demonstrated.

Phase errors deteriorate the quality of synthetic aperture radar (SAR) images drastically. In the practical automotive SAR data acquisition, the phase error varies for different regions of the observed area. It seems reasonable to consider a similar error for targets in a small region of the SAR image. In this work, we combine a generalized method of the phase gradient autofocus (PGA) and the fast factorized back-projection (FFBP) algorithm to estimate the phase error and reconstruct compensated sub-images. The proposed method is evaluated with multi-target scene simulations and practical experiments by using a 77-GHz radar system. We will show that the space-variant phase error estimator improves the image quality with a lower computational cost than conventional methods.

Phase error estimation and correction plays an essential role in high quality synthetic aperture radar (SAR) image formation. Especially in automotive applications, because of the highly non-linear driving paths, it is required to alleviate uncompensated motion errors. In this work, we use the general version of phase gradient autofocus (PGA) which is compatible with time-domain image formation algorithms. The adapted method overcomes the typical problems of conventional approaches and shows remarkable robustness against a large range of simulated errors. Furthermore, the proposed approach is evaluated on real radar data acquired by mounting a 77-GHz radar system on a bumper of a car. It is demonstrated that the implemented algorithm removes phase errors and improves the quality of automotive SAR image formation.

The requirement of fast analog-to-digital (AD) and digital-to-analog (DA) converters is a challenge for high-resolution orthogonal frequency division multiplexing (OFDM) radars. This paper introduces a method to increase the modulation bandwidth of an OFDM signal by using an additional frequency modulated continuous wave carrier to reduce the requirements for the AD/DA converters while maintaining a high unambiguous velocity range. Multiplexing of transmit antennas with OFDM is still possible with the combined modulation. The presented approach is verified by simulations and measurements. A reduction of AD/DA converter bandwidth by factor eight is achieved.

The system and transistor-level design of low-power millimeter wave (mm-wave) active tags in silicon is discussed in detail. Two active mm-wave tags with identical system architecture, padframe, and chip size were designed and fabricated in 55-nm SiGe BiCMOS and 45-nm SOI CMOS technologies, respectively. They feature a three-stage low-noise amplifier (LNA), a wake-up detector, a BPSK modulator, and two variable gain output stages, each driving a separate transmit antenna in antiphase. The wake-up detector can be used to switch OFF all the blocks except for the LNA and detector, thus further reducing power consumption. The measured performance of the SiGe and SOI chips is remarkably similar: 19- and 20-dB gain, 9- and 8-dB noise figure, and 25-/10.8-mW (active/idle) and 18-mW power consumption, respectively. The SiGe tag was flip-chip-mounted on a mini-PCB with one receive and two transmit antennas for system level functionality tests carried out over a distance of 5 m. The SiGe-tag wake-up sensitivity was verified to be −62 dBm, in excellent agreement with simulation results.

In this paper, an incoherent radar network based on integrated radar sensors is presented. It consists of radar sensor nodes with independently generated frequency-modulated continuous wave-modulated transmit signals, performing both monostatic and bistatic distance measurements. An architecture to operate such a cooperative bistatic network is introduced and an optimal parameterization of the system is presented. Several nonidealities of frequency synthesizers, that are important for such cooperative radar networks, are discussed and their influence on system performance is evaluated. A prototype of the cooperative bistatic network has been realized using highly integrated radar sensors at 122 GHz. Radar measurements using the prototype prove the feasibility and potential of the network approach. The complete signal processing chain is presented, including an adapted multilateration algorithm for target position estimation using all measured distances.

In this paper, a coherent multistatic radar network with a novel system architecture is presented, which circumvents the general problems of clock distribution and phase noise related signal-to-noise ratio (SNR) issues. The proposed network consists of a variable number of multiple-input multiple-output (MIMO) radar sensors and a variable number of repeater tags, all of which operate incoherently on the hardware level. In a minimum configuration, the network only consists of one MIMO radar sensor and a repeater tag. The theory behind such a multistatic network is mathematically derived and simulations are presented to show key aspects of the network, i.e. multistatic range and Doppler measurements as well as high resolution angle estimation exploiting a very large virtual aperture spanning the whole network. Measurements with one sensor and one repeater tag at 77 GHz are carried out to verify the simulations. The measurements show that the bistatic path between the sensor and repeater tag retains coherency., publishedVersion

In this paper, a printed circuit board (PCB)-based planar cross-polarized reflector is designed and fabricated for polarimetric radar calibrations at 77 GHz. The reflecting structure consists of a double-cladded substrate material with an etched strip grid on the front and a ground plane on the back. Initial design and parameter optimization are based on unit cell simulations. Next, a full-wave simulation of a small version of the structure is performed in order to verify the unit cell results and to consider edge effects at the boundaries of the finite surface. Finally, a 24cm × 24cm version of the optimized structure is fabricated and measured in an anechoic chamber with a fully polarimetric radar system operating at 77 GHz. The results are compared to that of a 45°-rotated dihedral. A measured cross-to co-polar isolation of 20 dB in boresight direction in the 76–78 GHz band proves the feasibility of the proposed structure.

Multipath propagation occurs in many situations of radar measurements in complex environments. The unwanted effects range from interference over the radar channels, which causes amplitude fading and a corrupted direction of arrival (DOA) estimation, to the detection of ghost targets in an angle of arrival of the multipath direction. Due to the different number of reflections, polarimetric radars are capable to separate certain multipaths from direct paths if the target is known in advance. Furthermore, it is possible to separate objects with different polarimetric features in DOA that are located in the same radial distance to the radar. In this paper, a new approach to DOA detection based on the coherent Pauli decomposition is presented. With this approach, important multipath and DOA effects are analyzed and measurement results at 77 GHz on canonical objects in an anechoic chamber are presented. The results prove the feasibility of the approach and demonstrate the occurring effects.

This paper describes the design considerations, integration issues, packaging, and experimental performance of recently developed D-Band dual-channel transceiver with on-chip antennas fabricated in a SiGe-BiCMOS technology. The design comprises a fully integrated transceiver circuit with quasi-monostatic architecture that operates between 114 and 124 GHz. All analog building blocks are controllable via a serial peripheral interface to reduce the number of connections and facilitate the communication between digital processor and analog building blocks. The two electromagnetically coupled patch antennas are placed on the top of the die with 8.6 dBi gain and have a simulated efficiency of 60%. The chip consumes 450 mW and is wire-bonded into an open-lid 5 × 5 mm2quad-flat no-leads package. Measurement results for the estimation of range, and azimuth angle in single object situation are presented.

Due to their outstanding performance in image recognition, the application of convolutional neural networks (CNNs) for classification of polarimetric radar images is investigated in this paper. At first, several artificial radar targets that differ in physical dimensions and polarimetric properties are designed and constructed. These targets are mounted on a rotary table in an anechoic chamber and are rotated in front of a fully polarimetric radar operating at 77 GHz. For each rotation angle step, the targets are measured, where all measurements are taken at several distances. Then, a CNN is used to classify the measurement results into one of three superordinate classes of the constructed radar targets, each containing two different subordinate targets (sub-targets). Focus is lied on class decisions and not identification of specific sub-targets. A decision is taken for each single rotation angle step measurement and also for a majority vote on five consecutive rotation angle step measurements. Promising accuracy results demonstrate the validity of the approach but also reveal several open issues for future research.

In upcoming years, the task of autonomous driving and the associated classification of road users will become increasingly important. For a robust classification, vehicle signatures that provide a set of independent physical scatter information about the vehicles are needed. Polarimetric radar cross section (RCS) object signatures offer the possibility to decompose the measured scattering matrix (S-matrix) into canonical scattering mechanisms, such as even- and odd-bounce, as well as crosspolar scattering. Classical single-polarized signatures, however, only depend on the co-polarized magnitudes and thus contain less information. Therefore, polarimetric RCS signatures are promising candidates for classification purposes. In this paper, polarimetric signatures at 77 GHz of four selected two-wheeled vehicle classes are presented. The test vehicles are rotated around their yaw axis and for each rotation angle step the range dependent polarimetric signature is measured. The polarimetric data is then processed by the coherent Pauli decomposition and the resulting signatures are presented. Furthermore, the polarimetric signatures are compared to their single-polarized versions.

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.

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.

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.

This paper describes the first fundamental frequency single-chip transceiver operating at -band. The low-IF monostatic transceiver integrates on a single chip two 120-GHz voltage-controlled oscillators (VCOs), a 120-GHz divide-by-64 chain, two in-phase/quadrature (IQ) receivers with phase-calibration circuitry, a variable gain transmit amplifier, an antenna directional coupler, a patch antenna, bias circuitry, a transmit power detector, and a temperature sensor. A quartz antenna resonator with 6-dBi gain and simulated 50% efficiency is placed directly above the on-chip patch to transmit and receive the 120-GHz signals. The circuit with the above-integrated-circuit antenna occupies an area of 2.2 mm 2.6 mm, consumes 900 mW from 1.2- and 1.8-V supplies, and was wire-bonded in an open-lid 7 mm 7 mm quad-flat no-leads package. Some transceiver performance parameters were characterized on the packaged chip, mounted on an evaluation board, while others, such as receiver noise figure and VCO phase noise at the 120-GHz output were measured on circuit breakouts. The AMOS-varactor VCOs have a typical phase noise of at 1-MHz offset and a tuning range of 115.2-123.9 GHz. The receiver gain and the transmitter output power are each adjustable over a range of 15 dB with a maximum transmitter output power of 3.6 dBm. The receiver IQ phase difference, measured at the IF outputs of the packaged transceiver, is adjustable from 70° to 110°, while the amplitude imbalance remains less than 1 dB. The receiver breakout gain and double-sideband noise figure are 10.5-13 and 10.5-11.5 dB, respectively, with an input compression point of . Several experiments were conducted through the air over distances of up to 2.1 m with a focusing lens placed above the packaged chip.

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.

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.

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.

In this paper, we present for the first time the realization of a 77 GHz chip-to-rectangular waveguide transition realized in an embedded Wafer Level Ball Grid Array (eWLB) package. The chip is contacted with a coplanar waveguide (CPW). For the transformation of the transverse electromagnetic (TEM) mode of the CPW line to the transverse electric (TE) mode of the rectangular waveguide an insert is used in the eWLB package. This insert is based on radio-frequency (RF) printed circuit board (PCB) technology. Micro vias formed in the insert are used to realize the sidewalls of the rectangular waveguide structure in the fan-out area of the eWLB package. The redistribution layers (RDLs) on the top and bottom surface of the package form the top and bottom wall, respectively. We present two possible variants of transforming the TEM mode to the TE mode. The first variant uses a via realized in the rectangular waveguide structure. The second variant uses only the RDLs of the eWLB package for mode conversion. We present simulation and measurement results of both variants. We obtain an insertion loss of 1.5 dB and return loss better than 10 dB. The presented results show that this approach is an attractive candidate for future low loss and highly integrated RF systems.

This paper shows a SiGe single chip radar sensor with high efficient LCP off-chip antennas integrated in a standard QFN package at a center frequency of 122.5 GHz. The millimeter-wave interconnect is performed by a CPW bond-wire connection with subsequent matching network. For demonstration purposes a complete baseband processing and RF unit is implemented on a PCB and integrated in a plastic housing where a focusing HDPE lens with a directivity of 30.7 dBi for gain enhancement can be connected. Distance measurements in a real world scenario are performed from 0.4-18.25m and 0.6-14.5m for a metal plate and a wooden plate, respectively. Additionally, a velocity measurement from 0.5-5m/s in the laboratory is performed.

This paper presents an integrated mixed-signal 120GHz FMCW/CW radar chipset in a 0.13μm SiGe BiCMOS technology. It features on-chip MMW built-in-self-test (BIST) circuits, a harmonic transceiver, software linearization (SWL) circuits and a digital interface. This chipset has been tested in a low-cost package, where the antennas are integrated. Above 100GHz, our transceiver has achieved state-ofthe-art integration level and receiver linearity, and DC power consumption.

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.

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.

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 novel ultrawideband (UWB) tapered slot antenna with high directivity is presented. It operates in the frequency range from 2.2 GHz up to 8.5 GHz. The antenna consists of three parts. As feed, a tapered slot on a PCB is used. Additional corrugations at the lateral metallic borders of the tapered structure lead to reduced side lobe levels and a flat gain in the main direction. The PCB is inserted into a cylindrical dielectric rod to increase the directivity. Finally a metallic reflector is added at the back of the antenna structure to reduce the backward radiation. With this design, a mean gain of 9 dBi and a stable main beam direction with a nearly constant 3 dB beam width, both in the E- and H-plane, were achieved. The antenna shows excellent time domain behavior with a high and sharp peak as well as low ringing of the impulse response.

A system simulation approach to model conducted emissions of a gearbox electronic control unit (ECU) is presented. The system is partitioned in ECU, cable harness, and load. The ECU itself is modeled using 3D electromagnetic simulation. For the cable harness and loads analytic models are employed, so that the incorporation of these parts into the model can be done without any increase in simulation time. The model is used to investigate resonances between PCB and housing, and common and differential mode currents on the cable harness. Also, optimal positions of critical subassemblies on the printed circuit board inside the ECU have been investigated.

This work has developed an ultrawideband tapered slot antenna in the frequency range from 2.2 GHz to 8.5 GHz. High directivity is achieved by using a dielectric rod as a waveguide and a metallic reflector. The antenna exhibits a stable main beam direction over the band of operation and a measured mean gain of 8.1 dBi. At 5.5 GHz, a 3 dB opening angle of 42deg and a front-to-back ratio better than 14 dB were realized.

Various microstrip coupler structures have been realized using high resistivity silicon on insulator (SOI) wafers. By applying an anisotropic etching process, membranes with a thickness of 50 mum are achieved. Thereby it is possible to realize low-loss microstrip circuits for millimeter-wave applications in F- band. This paper presents a side-coupled filter structure, a 10 dB directional coupler, a branch-line coupler, a rat-race coupler and a Wilkinson divider. The circuits are designed for the 122 GHz ISM band. The measured characteristics of the circuits agree well with the results achieved by momentum simulation.

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.

Fully monolithic integration of a millimeter wave system on silicon requires low loss passive circuitry. Transmission line elements are needed to interconnect active devices and to realize distributed passive components. Using bulk micromachining and high resistivity silicon on insulator (SOI) wafers, well defined thin silicon membranes can be manufactured. This allows the use of microstrip circuits on silicon substrates at frequencies beyond 100 GHz. Full wave simulation results accompanied by measurements are presented for coplanar to microstrip transitions, microstrip lines and two simple test circuits.

A rectangular microstrip patch antenna, realized as a silicon based monolithic millimeter-wave integrated circuit (SIMMWIC), is presented. The antenna was designed for an operating frequency of 122 GHz and manufactured on micromachined high resistivity silicon-on-insulator (SOI) substrate. Since direct measurements of the far field pattern of an integrated antenna element are difficult at this frequency, a scaled version of the antenna (with a resonant frequency of about 9.6 GHz) was also manufactured. Far field measurements were performed, to determine the antenna performance and compare with numerical results.

In this paper monolithically integrated IMPATT diodes are presented. To prove the concept of completely monolithic integration, no special heatsinks or other constructions to optimize cooling were used. The diodes were grown with molecular beam epitaxy on a high resistivity silicon substrate. S-Parameter measurements were performed from 85 GHz up to 110 GHz, showing high negative impedances above the avalanche frequency. Oscillations at a frequency near 93 GHz were observed with the designed resonator circuit.

Efficient transmission of high power microwaves and their launching can be achieved in corrugated waveguides by particular mixtures of hybrid modes. The optimum coupling of a free space Gaussian beam into a corrugated waveguide as well as forming of suitable launch patterns for diverse applications are investigated. There are many different schemes for mode conversion in corrugated waveguides to meet the specific requirements of different users. This paper reports on three different principles, a calculation method and a new type of mode converter based on varying the wall impedance, without inner diameter change.