Spurline Filter Research Articles

Microwave bio-sensor based on symmetrical split ring resonator with spurline filters for therapeutic goods detection.

A novel symmetrical split ring resonator (SSRR) based microwave sensor with spurline filters for detecting and characterizing the properties of solid materials has been developed. Due to the weak perturbation in the interaction of material under test (MUT) and planar microwave sensor, spurline filters were embedded to the SSRR microwave sensor which effectively enhanced Q-factor with suppressing the undesired harmonic frequency. The spurline filter structures force the presented sensor to resonate at a fundamental frequency of 2.2 GHz with the capabilities of suppressing rejected harmonic frequency and miniaturization in circuit size. A wide bandwidth rejection is achieved by using double spurlines filters with high Q-factor achievement (up to 652.94) compared to single spurline filter. The new SSRR sensor with spurline filters displayed desired properties such as high sensitivity, accuracy, and performance with a 1.3% typical percentage error in the measurement results. Furthermore, the sensor has been successfully applied for detecting and characterizing solid materials (such as Roger 5880, Roger 4350, and FR4) and evidently demonstrated that it can suppress the harmonic frequency effectively. This novel design with harmonic suppression is useful for various applications such as food industry (meat, fruit, vegetables), biological medicine (derived from proteins and other substances produced by the body), and Therapeutic goods (antiseptics, vitamins, anti-psychotics, and other medicines).

Frequency‐selectable dual‐band Wilkinson divider/combiner

A technique for realising a compact frequency-selectable dual-band Wilkinson divider/combiner is presented in this study. To provide a frequency-selection function, the band-pass transmission-line transformer (TLT) in a dual-band device is replaced with a tuneable band-reject TLT. To realise this tuneable device, a variable capacitively loaded spur-line filter is proposed for its compact size. The theory based on an ideal transmission-line circuit is developed to provide a design procedure. The proposed circuits are demonstrated with simulated and measured results of a Wilkinson divider/combiner fabricated on FR4 substrate.

Frequency switchable branch-line hybrid coupler

This article first presents a frequency-selectable branch-line hybrid coupler.To provide a frequency-selection function, a dual-band band-pass transmission-line transformer (TLT) with a frequency selective function is used. This is achieved by replacing a dual-band TLT with a variable capacitively loaded spur-line filter. The technique is demonstrated with a design at 0.8 and 1.75 GHz. Measured S-parameter results confirm the validity of the technique. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1661–1663, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27648

Miniaturisation and electronic tuning techniques for microstrip spurline filters

A new technique for the miniaturisation and electronic tuning of microstrip spurline filters is presented. The technique is based on connecting a reactive component across the end of the coupling gap of the spurline. The circuit is analysed by using a general coupled-line model, leading to the conclusion that, if a capacitance is used, the filter can be miniaturised or electronically tuned. The analysis leads to a set of simple design equations for these applications and a range of simulations are used to investigate the technique further. The validity of the techniques is demonstrated with three different practical circuits. For a miniaturised spurline filter operating at 1.8 GHz, 50% length reduction is achieved. Two varactor-tuned designs are described: a single-section and a cascaded spurline filter. The single-section spurline can be tuned across almost one octave bandwidth, from 580 MHz to 1.06 GHz whereas the cascaded design achieves tuning range of 320 -723 MHz.

Design of asymmetrical spurline filter for a high power sic MESFET class-E power amplifier

An asymmetrical spurline filter (ASF) with dual-bandgap characteristics is designed and applied as the load network of the class-E power amplifier to improve the output power and efficiency. Meanwhile, an equivalent circuit model is built for the proposed ASF based on two LCR resonators. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1650–1652, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25260

Dual‐bandgap characteristics of spurline filters and its circuit modeling

AbstractA novel asymmetrical spurline filter is introduced in this article. Its dual‐bandgap characteristics are reported for the first time and can be adjusted by changing the difference between the two spurlines' lengths. Moreover, a simple circuit model is set up for the new filter by using two LCR‐resonators. The proposed spurline filter and its circuit model are discussed and verified by a good agreement between simulations and measurements. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2805–2807, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22862

Compact microstrip bandstop filter using open stub and spurline

A compact wideband high-rejection microstrip bandstop filter (BSF) is presented. This filter combines two traditional BSFs: open-stub filter and spurline filter. Due to the inherently compact characteristics of the spurline, the proposed filter shows a better rejection performance than open-stub BSF without increasing the circuit size. From 3.7 to 5.4 GHz, the proposed BSF has a rejection of better than 20 dB and the maximum rejection level of 61 dB. Application of this BSF to suppress the second harmonic of an open-loop ring bandpass filter is also investigated with a 40-dB suppression improvement achieved.

Compact dual‐band antenna for mobile handsets

AbstractA compact antenna suitable for personal communication handsets is presented. The antenna consists of a rectangular patch with a shorting pin. A spur‐line filter was added to obtain a dual‐band operation. Details of the antenna design are discussed, along with simulated and measured results. © 2002 John Wiley & Sons, Inc. Microwave Opt Technol Lett 32: 87–88, 2002

A comparison of dual‐band spur‐line printed antennas for handheld terminals

AbstractRecent breakthroughs in mobile phone technology are focusing on new techniques that allow the compact integration of dual‐band printed antennas into handsets with an increase in their inherent narrow bandwidth. In this letter, novel rectangular, circular, triangular, hexagonal, and bow‐tie‐shaped spur‐line dual‐band printed structures have been designed, measured, and compared. Although a second resonant frequency is obtained, it has been clearly made evident that spur‐line filter techniques are unable to obtain broad‐bandwidth elements, unless they can be combined with other methods. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 205–207, 2001.

Triple band microstrip patch antenna using a spur-line filter and a perturbation segment technique

A triple-band microstrip patch antenna is demonstrated by using a spur-line bandstop filter and a perturbation segment technique. This multifrequency operation can be obtained without increasing either the size or the thickness of the patch. In addition, through experimental results, the characteristics in all channels are shown to be nearly identical.