Wolfgang Menzel

Broadband Via-Free Microstrip Balun Using Metamaterial Transmission Lines

A novel metamaterial broadband microstrip balun design is proposed. The broadband balun consists of a pair of identical metamaterial transmission lines. In the odd mode, a virtual ground is formed between the symmetric plane. The odd mode is allowed while the even mode is rejected. No vias are required to realize the shunt inductors of the metamaterial lines, and no power divider is used. Baluns with good performance can be achieved. In this letter, two baluns are fabricated and measured. For the balun with seven units, the output amplitude difference is less than 0.7 dB, and the differential phase is 181deg plusmn 3deg from 1.6 to 3.6 GHz, while the input return loss is greater than 10 dB.

A Simple Ultra-Wideband Suspended Stripline Bandpass Filter With Very Wide Stop-Band

This letter introduces a simple ultra-wideband suspended stripline filter with a pass-band from 3.1 to 10.6 GHz and a very wide stop-band up to more than 25 GHz. The filter is realized by capacitive coupling of a quasi-lumped low-pass filter to the I/O ports. Insertion loss in the pass-band is better than 0.5 dB. The filter has a length of 13.8 mm. Excellent agreement is achieved between measured and simulated results.

Millimeter-Wave-Radar Sensor Based on a Transceiver Array for Automotive Applications

This paper describes a new radar sensor architecture comprising an array of transceiver modules. Target applications of the sensor are automotive driver assistance systems. In conjunction with a monolithic integration of each transceiver, the concept offers the possibility for a cost-effective realization of digital-beamforming radar sensors at millimeter-wave frequencies. A modulation sequence is investigated based on simultaneously transmitted frequency-modulated continuous-wave signals, which are separated by frequency multiplexing. Appropriate signal processing for the estimation of range, speed, and azimuth angle in multiple object situations is presented. Experimental results with an eight-channel radar sensor in the 76-77-GHz frequency band are presented, which demonstrate the feasibility of the proposed architecture and show the performance of the modulation sequence and signal processing.

Foreign Objects Debris Detection (FOD) on Airport Runways Using a Broadband 78 GHz Sensor

This paper describes a compact broadband (73-80 GHz) mm-Wave front-end used for FOD detection application. The design philosophy of our system is to have several low-profile, low-cost mm-Wave sensors placed along the runway. Tests were conducted on the small airport of Aix Les Milles (south of France). High sensitivity and simultaneous objects detection capabilities were shown. Even very small objects like nuts were seen. The extension of the actual detection range is needed in order to go from 110 m (in the most favourable case) to 500 m.

Modeling and Optimization of Compact Microwave Bandpass Filters

This paper presents the modeling and optimization of compact microwave bandpass filters whose compactness leads to complex and strong stray coupling paths, thereby making the identification of a simple and sparse coupling topology difficult and even impossible. The strong coupling coefficients needed for a broadband response can also cause an ambiguity in identifying the spatial extent of local resonances. An equivalent circuit, which is extracted directly from Maxwells equations, is used in optimizing these filters. The filter is represented by its global resonances instead of individual resonators. The extraction of the parameters of the equivalent circuit is carried out in the physical frequency and not in the normalized frequency in order to preserve the physicality of the equivalent circuit, especially for asymmetric responses. The technique is successfully applied to the optimization of second-order suspended stripline bandpass filters with one transmission zero either below or above the passband, as well as fourth-order filters with three transmission zeros. A fourth-order filter with three transmission zeros is fabricated and measured.

A wide band transition from waveguide to differential microstrip lines

A novel transition from rectangular waveguide to differential microstrip lines is illustrated in this paper. It transfers the dominant TE10 mode signal in a rectangular waveguide to a differential mode signal in the coupled microstrip lines. The common mode signal in the coupled microstrip lines is highly rejected. The transition was designed at 75 GHz, which is the center frequency of E band and simulated by a 3D EM simulator. It has a wide bandwidth of 19 GHz for -15 dB return loss of the waveguide port. Several prototypes of the transitions were fabricated and measured. The measurement results agree very well with the simulation. The compact size and the simple fabrication enable the transition to be employed in a number of millimeter-wave applications.

Highly compact impulse UWB transmitter for high-resolution movement detection

In this paper the hybrid integration of an FCC-compliant fifth-order Gaussian derivative impulse generator IC together with a compact ultra-wideband Vivaldi antenna is presented. The setup results in a compact FCC-compliant impulse UWB transmitter. Measurements of the impulse shape in time and spectral domain are shown. With this transmitter a movement detection and the precise measurement of the movement deviation value by a correlation measurement technique is presented. This shows the ability of the UWB radar system to operate as a movement detection sensor. The measurements include a breath rate measurement of a human being.

Hybrid Integrated RF-MEMS Phased Array Antenna at 10GHz

In this paper, a one-dimensional electrically steerable RF-MEMS phased array antenna for operation at 9.5 GHz is demonstrated. The antenna itself is a four by eight patch antenna array realised on low-loss Teflon substrate and the feed network made out of the same substrate is a one-to-four corporate feed network. The phase shifting necessary to steer the main beam of the antenna in the H-plane of the aperture is achieved by four 3 bit RF-MEMS phase shifters, which are integrated in a hybrid fashion between the antenna and the feed network. The paper describes the integration of the different elements in a standalone phased array antenna demonstrator. The design of the 3 bit RF-MEMS phase shifters is presented and validated by very good measurement results. Finally, the measured radiation characteristic of the complete phased array antenna is shown for different switching states of the phase shifters.

LTCC Patch Array for RF-MEMS based Phased Array Antenna at 35GHz

In this paper, a LTCC patch antenna array for Ka-band RF-MEMS based electrically steerable antenna is demonstrated. The paper presents a novel hybrid integration concept for the RF-MEMS phase shifters intended to steer the main beam of the antenna in the H-plane of the aperture. According to the proposed configuration, the phase shifters realised in silicon technology are packaged using LTCC lids bonded on top of the silicon chips and are flip-chip mounted on the antenna realised on LTCC. The architecture allows for the realisation of highly integrated RF-MEMS based phased array for millimetre-wave front-ends and aims at reducing the complexity and costs of such modules. The design of the four by four aperture coupled patch antenna array is validated by satisfactory measurement results. A study of the repeatability of the LTCC process used to fabricate the antenna is carried out over a population of five samples and the behaviour of the matching of the antenna over temperature is investigated.

High Q Micro-machined Cavity Resonator Filter in Low-Cost Silicon Technology

This paper demonstrates a two-pole filter based on high Q micro-machined cavity resonators for operation at 20 GHz. The filter implements a novel inter-resonator coupling cavity placed above the inter-cavity wall separating the resonators and etched out of silicon using the same KOH-etching process as the one used to realised the cavity resonators. The Q-factor of a single cavity resonator is measured as well as the response of the two-pole filter. The filter presented here constitutes the first development step toward a more sophisticated fixed as well as tunable four-pole filter aiming at the replacement of bulky waveguide filters mounted in a majority of satellite transceivers.