Carsten Metz

Reducing Cross-Target Products in Thinned Antenna Arrays using Nonlinear Processing

Antenna array thinning by nonlinear multiplicative processing of subarray signals is highly efficient. It allows thinning rates of up to 90% and is, therefore, very profitable for phased or digital beamforming radar arrays to save significantly on the cost of the antenna elements. However, thinning by multiplicative processing does not come without problems, such as false responses in complex multiple-target situations due to cross-target product terms. The reasons for the occurrence of these ghost targets will be outlined in this paper and a new method to counteract them will be presented. Measurements carried out at 77 GHz are consulted to assess the applicability and the benefit of the proposed method to high resolution radar.

Dynamic multiband antenna system for high capacity data communications to mobile platforms

A multiband phased array antenna solution is presented which allows to exceed capacity limitations of current fixed beam wireless transmission systems. Due to its small geometrical footprint the antenna lends itself especially for basestation and vehicular integration. For maximum diversity each band is covered by two orthogonal polarizations. A hybrid radiator feeding is introduced to adjust phase center separation and asymmetry of the primary radiation patterns. All crucial antenna parameters are discussed in view of their compatibility to legacy static beam hardware and their performance impact for the case that the array is deployed in a multichannel radio environment

Nonlinear system performance of shared amplifiers based on 3-way microstrip phase combiners

A nonlinear system analysis of a medium power 3-way shared amplifier is presented. It includes a first time practical verification of the new concept using a medium power setup at a design frequency of 1.9 GHz with an operational bandwidth of more than 300 MHz. The splitters and combiners are based on a novel, size-reduced planar multilayer microstrip implementation of a previously proposed coaxial 3-way phase combiner. The shared amplifier provides a gain of 12.85 dB in linear mode with excellent sector isolation of more than 30 dB. In large signal operation, a 5dB improvement in 1 dB-compression point and odd-order intercept points could be achieved compared to a single amplifier. We discovered a unique feature of coherently eliminating 3rd-order intermodulation products using only two channels of this setup. This effect is explained by theory and validated by measurements.