International Journal

This paper proposes the design of tunable dual-band resonators for multi-band multi-standard systems. The main objective is to provide frequency tunability in the second resonance while maintaining the first resonance fixed. To this end, two tunable resonators are proposed: the capacitive-loaded stepped-impedance resonator and the capacitive-loaded hole resonator. The work is divided into two main

The article describes the IRCTR PARSAX radar system, the S-band high-resolution Doppler polarimetric frequency modulated continuous wave (FM-CW) radar with dual-orthogonal sounding signals, which has the possibility to measure all elements of the radar target polarization scattering matrix simultaneously, in one sweep. The performance of such radar depends of the level of sounding signals orthogon

This paper presents an experimental investigation of two approaches to short-range radar imaging at microwaves by means of ultra-wideband (UWB) technology. The first approach represents a classical synthetic aperture radar (SAR) that employs a transmit?receive antenna pair on mechanical scanner. The second one makes use of a multiple input multiple output (MIMO) antenna array that scans electronic

This paper presents the design and implementation of an inverse class-F power amplifier (PA) using a high power gallium nitride high electron mobility transistor (GaN HEMT). For a 3.5 GHz continuous wave signal, the measurement results show state-of-the-art power-added efficiency (PAE) of 78%, a drain efficiency of 82%, a gain of 12 dB, and an output power of 12 W. Moreover, over a 300 MHz bandwid

This paper describes some key points in the history and development of the European Microwave Conference, the European Microwave Week, and the European Microwave Association, starting from 1969. It captures the way in which the conference since the earliest days has sought to create a successful blend of scientific and industry interests and has adapted itself to and indeed shaped the many existin

A novel scheme involving experimental analyses and diagnoses is presented for monitoring radio-frequency (RF) and high-speed circuits. A live electrooptic imaging (LEI) camera is used in the scheme and it provides real-time images of the phase evolution of the RF electric field. Besides, it is demonstrated that essential properties of RF wave propagation are easily grasped from visual images; exam

This contribution deals with guided radar distance measurements in the field of industrial tank level control. The aim is to achieve a submillimeter gauging accuracy even when conducting the measurement within a highly dispersive environment of large and thus overmoded circular waveguides. Normally, multimode propagation causes a decrease in measurement precision. Therefore, the effects of intermo

TanDEM-X (TDX; TerraSAR-X add-on for digital elevation measurement) is an innovative spaceborne X-band earth observation mission that will be launched in June 2010. This paper gives an overview of the TDX mission concept, summarizes the basic products and illustrates the achievable performance. In more detail the effect of quantization on the interferometric performance is discussed. Finally, new

This work presents the design, manufacturing, and testing of three 5-bit K-band Micro-Electro-Mechanical-Systems (MEMS) phase shifters based on similar architectures (combination of switched line and loaded line) but employing different MEMS switch typologies (cantilevers and air bridges) and RF junctions (SP2T and SP4T). All devices have been monolithically manufactured on 200 µm thick high resis

New technologies have resulted in transmission lines that deviate significantly from the intended rectangular cross sections. Trapezoidal cross sections and roughness that penetrate a significant depth into the surface in comparison to the skin-depth of the conductor can cause a very significant deviation in transmission line parameters from predicted values. Proximity effect further complicates t