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RF-MEMS variable matching networks and switches for multi-band and multi-mode GaN power amplifiers
This work presents radio-frequency-microelectromechanical-system (RF-MEMS)-based tunable matching networks for a multi-band gallium nitride (GaN) power amplifer (PA) application. In the frequency range from 3.5?8.5 GHz return losses of 5?10 dB were measured for the input network, matching impedances close to the border of the Smith chart. For the output matching network return losses of 10?20 dB a
Dynamic interference suppression for chipless wireless sensors based on an out-of-band channel estimation method
A channel estimation method for chipless wireless sensors is presented. The method is developed to suppress interference signals in radio frequency backscatter systems. It uses two adjacent frequency bands to estimate and suppress the disturbing signal of a dynamic interferer. Afterwards a correction of the sensor tag's backscatter signal is achieved. The method has been tested in indoor measureme
Design of a broadband passive X-band double-balanced mixer in SiGe HBT technology
In this paper, a passive double-balanced mixer in SiGe HBT technology is presented. Owing to lack of suitable passive mixing elements in the technology, the mixing elements are formed by diode-connected HBTs. The mixer uses lumped element Marchand baluns on both the local oscillator (LO) and the radio frequency (RF) port. A break out of the Marchand balun is measured. This demonstrates good phase
Active textile antennas in professional garments for sensing, localisation and communication
New wireless wearable monitoring systems integrated in professional garments require a high degree of reliability and autonomy. Active textile antenna systems may serve as platforms for body-centric sensing, localisation, and wireless communication systems, in the meanwhile being comfortable and invisible to the wearer. We present a new dedicated comprehensive design paradigm and combine this with
Study and analysis of contiguous channel triplexer based on combining method of two filtering circuits using CRLH and RH isolation circuits
Several types of multiplexers based on isolation circuits have been introduced and investigated. Combining method of two filtering circuits (CMTC) is one way to make multiplexers based on isolation circuits. This method fits well for designing contiguous channel triplexers. A triplexer based on CMTC consists of a conventional transmission line (TL) connected to a diplexer and a composite right/lef
243 GHz low-noise amplifier MMICs and modules based on metamorphic HEMT technology
Two compact H-band (220?325 GHz) low-noise millimeter-wave monolithic integrated circuit (MMIC) amplifiers have been developed, based on a grounded coplanar waveguide (GCPW) technology utilizing 50 and 35 nm metamorphic high electron mobility transistors (mHEMTs). For low-loss packaging of the circuits, a set of waveguide-to-microstrip transitions has been realized on 50-?m-thick GaAs substrates d
Hybrid SIMO and MIMO sparse array radar
This paper clarifies what we benefit from single-input?multiple-output (SIMO) or multiple-input?multiple-output (MIMO) radar. We have developed an X-band sparse array imaging radar system capable of operating at both SIMO and MIMO modes. The hybrid radar modes are realized without any modification in hardware, but simply by switching the scheme of waveform generation and post-processing. A compari
Design, simulation, and fabrication of broadband coaxial matched loads for the frequency range from 0 to 110 GHz
Combining a theory for reflection-free termination of coaxial lines together with a novel manufacturing method results in 1-mm coaxial matched loads with an excellent absorption behavior over the frequency range from 0 to 110 GHz. Three different electromagnetic (EM) simulation approaches verify the capability of these matched loads to achieve reflection coefficients smaller than ?43 over the ent
Self-similarity matrix based slow-time feature extraction for human target in high-resolution radar
A new approach is proposed to extract the slow-time feature of human motion in high-resolution radars. The approach is based on the self-similarity matrix (SSM) of the radar signals. The Mutual Information is used as a measure of similarity. The SSMs of different radar signals (high-resolution range profile, micro-Doppler, and range-Doppler video sequence) are compared, and the angel-invariant pro
Threat object classification with a close range polarimetric imaging system by means of - decomposition
In this paper, an approach to differentiate between various dielectric threat objects in security applications is investigated. The scattering information in form of the Sinclair matrix of relevant scenarios is gained from a fully polarimetric, synthetic aperture radar. Both monostatic and multistatic array configurations are examined. A possible polarimetric calibration procedure is presented. Th