Frequenz 

About: Frequenz is an academic journal published by De Gruyter. The journal publishes majorly in the area(s): Antenna (radio) & Computer science. It has an ISSN identifier of 0016-1136. Over the lifetime, 2840 publications have been published receiving 10661 citations. The journal is also known as: Frequenz (Berlin. Print).

Robust OP Amp realization of Chua's circuit

Abstract: Chua's circuit is a simple electronic network which exhibits a variety of bifurcation phenomena and attractors. The circuit consists of two capacitors, an inductor, a linear resistor, and a nonlinear resistor. This paper describes the design methodology for a robust practical op amp implementation of Chua's circuit. In addition, we present experimental results and SPICE simulations for a working circuit using o -the-shelf components.

Shuttle Radar Topography Mission (SRTM) Mission Overview

Abstract: The first single pass SAR (synthetic aperture radar) interferometer in space has been flown after some delay on board the Space Shuttle in February 2000. The mission is called SRTM (Shuttle Radar Topography Mission). The mission objective was to acquire a radar data set during this 11 day mission which allows to generate a new consistent and more accurate global digital terrain model and topographic maps of all land surfaces between +60 and -56 latitudes and it has been successfully achieved.

Defected Ground Structure in the perspective of Microstrip Antennas: A Review

Abstract: Defected ground structures (DGS) have been developed to improve characteristics of many microwave devices. Although the DGS has advantages in the area of themicrowave filter design, microwave oscillators, microwave couplers to increase the coupling, microwave amplifiers, etc., it is also used in the microstrip antenna design for different applications such as antenna size reduction, cross polarization reduction,mutual coupling reduction in antenna arrays, harmonic suppression etc., TheDGS ismotivated by a study of Photonic/Electromagnetic Band gap structures. The etching of one or more PBG element creates defect in the ground plane and used for the same purpose. The DGS is easy to be an equivalent L-C resonator circuit. The value of the inductance and capacitance depends on the area and size of the defect. By varying the various dimensions of the defect, the desired resonance frequency can be achieved. In this paper the effect of DGS, to the different antenna parameter enhancement is studied. Index Terms – Defected Ground Structure, Microstrip Antennas.

Realization of a class of analog signal processing / signal generation circuits : Novel configurations using current feedback op-amps

Abstract: In this paper, we demonstrate that, when treated as 4-terminal building blocks, the current feedback op-amps (CFOA) or transimpedance op-amps are more versatile than the traditional 3-terminal op-amps and 3-terminal Current Conveyors (CC), In realising a class of analog signal processing / signal generation functions which include impedance converters / inverters, voltage-controlled impedances (both grounded and floating), active filters (both current mode and voltage mode) and single-resistance-controlled/voltage-controlled sinusoidal oscillators. Novel CFOA-based configurations are, therefore, derivable which provide features all of which are not possible with the available op-amp-based or CC-based reallsations. The workability of the new structures is substantiated by experimental results based upon the commercially available transimpedance op-amp AD844.