Signal-interference Techniques Research Articles

Ultra‐wideband (UWB) power divider based on signal interference techniques

AbstractA novel ultra‐wideband (UWB) power divider based on signal interference techniques is presented. The short‐ended symmetrical coupled‐line and transversal transmission line are introduced at both output ports of the power divider. The proposed power divider is analysed with the even and odd mode approach. Simple design procedure and several equations can be applied to find the parameters of the device. A prototype power divider is designed and fabricated to demonstrate the performance of the UWB power divider structure. Experimental results show good performance in UWB passband. In addition, a stopband with over 20 dB attenuation is from 12.2 to 17.2 GHz. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1028–1030, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26745

High-rejection wide-stopband lowpass filters using signal interference technique

A design of compact, sharp rejection microstrip lowpass filters (LPF) with wide-stopband is presented by using signal interference technique. The filter parameters can be easily controlled by the characteristic impedances of the configuration. Explicit design equations with graphs are presented. To validate the theoretical prediction, two prototype LPFs are fabricated. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010.

A Type of Planar Array-Antenna Feeding Network With Single/Multiband Filtering Capability

A dual-function circuit carrying out both the RF power-division and single/multiband filtering action is presented. It is used as building element to develop highly frequency-selective power-distribution networks for planar array-type antennas. The operating principle of this filtering/feeding circuit, exploiting transversal signal-interference techniques, is described. Also, formulas and guidelines helping in its theoretical design are given. As proof of concept, microstrip prototypes of four-way single- and triple-band filtering/feeding networks are built and tested.

A Class of Microwave Transversal Signal-Interference Dual-Passband Planar Filters

A new type of microwave dual-passband planar filter exploiting signal-interference techniques is presented. The described filter approach consists of transversal filtering sections shaped by two transmission lines connected in parallel. This transversal section, operating under feedforward signal-combination principles, allows dual-band bandpass filtering responses with several transmission zeros to be synthesized. A set of analytical formulas and guidelines for the design of the dual-passband transversal filtering section are provided. Moreover, its practical usefulness is verified through the development and testing of a microstrip prototype for the 1.4/2.6-GHz dual band.

Design of compact, wide‐band bandstop filters with sharp‐rejection characteristics

AbstractIn this study, a novel transmission line configuration has been proposed to design a sharp‐rejecting, compact bandstop filter with wide rejection‐bandwidth. Signal interference technique is used to obtain transmission zeros, which provide the sharp rejection characteristic. Rejection bandwidth is controlled by the characteristic impedances of transmission lines. Filter is analyzed using transmission line model. Theoretical predictions have been verified by the measurements of two compact filters fabricated in microstrip line. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1244–1248, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23335

A Compact Wideband Bandpass Filter Using Transversal Resonator and Asymmetrical Interdigital Coupled Lines

A compact wideband microstrip bandpass filter using transversal resonator and asymmetrical interdigital coupled lines is proposed in this letter. A wide passband is first constructed using transversal signal-interference technique, resulting a pair of transmission zeros at each side of the desired passband. By driving this transversal resonator with two asymmetrical interdigital coupled lines at two sides, five extra transmission zeros are generated in the lower/upper stopbands with excellent dc-choked property, thus making up a wide passband with improved out-of-band performance. This wideband microstrip filter is then designed, implemented and experimented. Good insertion/return losses, flat group delay and good out-of-band rejections are achieved as demonstrated in both simulation and experiment.

Compact bandstop filter using signal interference technique

A signal interference technique is proposed to design a compact wideband bandstop filter (BSF). Two parallel transmission lines of different lengths and characteristic impedances are used. The signal propagates through these two paths and interferes at the other end with different phases and magnitudes. By varying these phases and magnitudes two finite transmission zeros can be obtained. To improve the stopband rejection level another zero is obtained using an open-circuited quarter-wavelength stub at the stopband centre frequency (fc). One single section prototype fabricated BSF of fc=0.449 GHz has 3 and 40 dB fractional bandwidths of 50.6 and 22.3%, respectively. The filter implementation area is 0.116λg×0.163λg, λg being the guided wavelength at fc.

High-rejection wideband signal-interference microstrip filters using rat-race couplers

A new type of sharp, high-rejection wideband microstrip filter based on signal-interference techniques is reported. The proposed topology uses, for the first time, rat-race couplers operating as transversal filtering sections (TFSs). Design equations and guidelines for this TFS are provided. Furthermore, to prove its experimental usefulness, a 6.5 GHz ultra-wideband prototype has been synthesised, constructed and measured.

Design of sharp-rejection and low-loss wide-band planar filters using signal-interference techniques

A new class of sharp-rejection, low insertion-loss wide-band planar filters is presented in this letter. The proposed filter topology uses transversal signal-interference filtering sections made up of two transmission-line segments connected in parallel. Thus, under signal-interaction principles, the filtering action comes about through the generation of multiple out-of-band power transmission zeros and constructive in-passband signal combinations. Design equations and guidelines to adjust both the bandwidth and the out-of-band performance of the filtering response through the design parameters of the transversal section are also provided. Furthermore, the theoretical results are validated with the manufacture and characterization of an ultra-wideband microstrip filter prototype at 5 GHz.