A Compact 1:4 Lossless T-Junction Power Divider Using Open Complementary Split Ring Resonator

This paper presents the size miniaturized and harmonic suppressed lossless 1:4 T-junction unequal power divider using an open complementary split ring resonator (OCSRR). By embedding the OCSRR structure in the microstrip transmission line, slow wave effect is introduced and thereby size reduction is achieved. The dimensions of OCSRR are optimized to reduce the length of high impedance and low impedance quarter-wavelength transmission lines. In our design high impedance line length is reduced to 58.6%, and low impedance line length is reduced to 12% when compared to the conventional quarter wavelength lines. The proposed power divider is having small dimensions of 0.18 λg × 0.33 λg and is 51.94% smaller than the conventional unequal power divider

Performance and emissions of compression ignition engine fueled with preheated blend of vegetable oil

Now days fossil fuel has been a problem that can been use in a compression ignition engine. Straight vegetable oil is one of the most reliable fuel that suitable for diesel engine. The scope of study of this study is focused on performance and emission of the straight vegetable oil from the grocery store to compare with crude palm oil from UTHM pilot plan. S5, S10 and S15 straight vegetable oil fuel is used for this experiment. This straight vegetable oil is also compared with an natural diesel in a combustion-ignition engine. The test is conducted with UTHM dynomometer which is located at automotive lab. The properties of the vegetable oil is tested for density, kinematic viscosity, water content, acids value and flash points. Brake power, flywheel torque, (in term of hydrocarbon, carbon monoxide, carbon dioxide, oxygen content and smoke opacity) and tested for performance and emission. Results obtained show that flywheel torque that has been produced from the biodiesel fuels are less than the natural diesel (ND). Biodiesel emission results shown a better emission compared to the ND fuels. The CO2, CO, HC and O2 content that released from the biodiesel fuels are clearly lower than the ND fuels. At low engine speed, biodiesel smoke opacity contents are quite high produces compared to the OD and other type o

Compact Multi-Band Differential Bandpass Filters and Diplexers Based on Multimode Resonators

埼玉大学博士(工学)vi, 128 p.In modern RF/microwave front-ends of transceivers, RF/microwave filters and diplexers are key passive components for realizing high performance of the systems. In recent years, differential circuits have attracted much attention because of their ability of rejecting common-mode (CM) noise and increasing significantly the immunity and sensitivity of communication systems. In this dissertation, novel microstrip dual-mode, quadruple-mode, and sext-mode resonators are proposed, and by using these resonators, four compact multi-band differential bandpass filters (BPFs) and one diplexer are developed to meet the increasing demand for high-immunity and high selectivity BPFs in future communication systems. First, a novel stepped-impedance square ring loaded resonator (SRLR) with quadruple-mode resonant characteristics is proposed. Compared with conventional SRLRs, the new stepped-impedance SRLR can provide one more design freedom to reach a large frequency separation between differential-mode (DM) resonances and common-mode (CM) resonances, and this is very important in the design of multi-band differential BPFs with high CM noise suppression. Moreover, the frequency discrepancy technique is applied in the filter design to separate the CM resonances in adjacent resonators so that the transmission of CM signals is weakened, and the CM suppression is increased. By using the new quadruple-mode stepped-impedance SRLRs, a compact second-order dual-band differential BPF is developed. Source-load coupling after adding two short microstrip lines is introduced to produce multiple transmission zeros and improve significantly the frequency selectivity of DM passbands. The experimental results agree well with the design simulation, which verifies well the proposed structure and design method. Next, by loading two additional open-circuited stubs to the above SRLR, a new sext-mode stepped-impedance SRLR is obtained. The new resonator has six resonant modes, including three DM resonances and three CM resonances. The operating mechanism of these resonances are investigated by using the even-and odd-mode method and simulation techniques. Three DM resonances are used to configure a second-order tri-band differential BPF. The filter is fabricated, and the measured frequency response agrees well with the theoretical prediction and verifies the proposed resonator and design concept. The measured passband insertion losses in the above second-order filters are relatively large (about1～2dB) because of the relatively large surface resistance of copper film commonly used in planar microwave circuits. To overcome this problem, the high-temperature superconducting (HTS) techniques are introduced in developing multi-band BPFs, because the HTS film has a surface resistance two- to three- order lower than the normal copper film at low microwave frequencies. In this dissertation, a fourth-order HTS dual-band differential BPF is developed using modified SRLRs, and its measured passband insertion loss is better than 0.16 dB. An eighth-order HTS dual-band differential BPFs is developed using symmetric-stub-loaded resonators, and its measured passband insertion loss is better than 0.35 dB. In the design of these two filters, independent control of both the midband frequencies and the bandwidths of the two passbands are achieved. Benefiting from the HTS technology and the precise design, the fabricated filters show excellent performance such as extremely low insertion loss, high frequency selectivity, and deep CM suppression, which are not realizable using normal conductor substrates. Finally, a compact 2.45/3.45 GHz diplexer is developed by using a novel hybrid resonant structure. The proposed structure consists of a microstrip stub-loaded dual-mode resonator (MSLDR) and a slotline stub-loaded dual-mode resonator (SSLDR). These two dual-mode resonators are placed on the top and bottom layer of a substrate, respectively, forming two separate signal channels of the diplexer. No matching network is required in the circuit, which simplifies the design of the diplexer, and reduce significantly the circuit size.ACKNOLEDGEMENTS.................................................................................................... I SUMMARY............................................................................................................ II CONTENTS........................................................................................................... IV Chapter 1 Introduction.............................................................................................. 1 1.1 Motivation and Objectives...................................................................................... 1 1.2 Literature Review on Multiband Differential Filters............................................... 3 1.3 Literature Review on Diplexers............................................................................. 10 1.4 Major Contributions of This Dissertation.............................................................. 14 1.5 Organization of the Dissertation............................................................................ 15 Chapter 2 Fundamental Elements of Circuits Design and HTS Technology... 17 2.1 Overview....................................................................................................... 17 2.2 Baic Models of Differential Filters and Diplexers................................................ 17 2.2.1 Basic Model of Differential Filters.................................................................. 17 2.2.2 Basic Model of Diplexers................................................................................ 19 2.3 Fundamentals of Microwave Filters...................................................................... 20 2.3.1 General Definitions......................................................................................... 20 2.3.2 Coupled Resonator Filters............................................................................... 21 2.3.3 Quality Factors of Microwave Filters.............................................................. 25 2.3.4 Filter Design Procedure................................................................................... 26 2.4 Fundamentals of HTS Technology........................................................................ 31 2.4.1 Characteristics of HTS materials..................................................................... 31 2.4.2 Substrates for Superconductors....................................................................... 36 2.4.3 Device Processing........................................................................................... 37 2.5 Conclusion..................................................................................................... 38 Chapter 3 Multi-Band Differential Bandpass Filters Based on SI-SRLRs....... 39 3.1 Overview...................................................................................................... 39 3.2 Dual-Band Differetial Bandpass Filter Based on Quadruple-Mode SI-SRLR...... 40 3.2.1 Analysis of Quadruple-Mode SI-SRLR.......................................................... 40 3.2.2 Dual-Band Differential Filter Design.............................................................. 44 3.2.3 Performance Improvement.............................................................................. 50 3.2.4 Experimental Results and Discussion............................................................. 52 3.3 Tri-Band Differential Bandpass Filter Based on Sext-Mode SI-SRLR................ 54 3.3.1 Analysis of Sext-Mode SI-SRLR.................................................................... 54 3.3.2 Tri-Band Differential Filter Design................................................................. 57 3.3.3 Performance Improvement.............................................................................. 58 3.3.4 Experimental Results and Discussion............................................................. 59 3.4 Conclusion.................................................................................................... 60 Chapter 4 High-Order Dual-Band HTS Diffenrential Bandpass Filters........... 61 4.1 Overview...................................................................................................... 61 4.2 Fourth-Order Dual-Band HTS Differential Bandpass Filter................................. 62 4.2.1 Analysis of the Modified SRLR........................................................... 63 4.2.2 Fourth-Order Dual-Band HTS Differentia Filter Design................... 70 4.2.3 Wideband CM Suppression...................................................................... 82 4.2.4 Experimental Results and Discussion...................................................... 84 4.3 Eighth-Order Dual-Band HTS Differential Bandpass Filter................................. 86 4.3.1 Analysis of the Multimode SSLR........................................................ 86 4.3.2 Eighth-Order Dual-Band HTS Differential Filter Design................... 90 4.3.3 Experimental Results and Discussion...................................................... 99 4.4 Conclusion.................................................................................................... 101 Chapter 5 Compact Diplexer Using Hybrid Resonant Structure..................... 102 5.1 Overview...................................................................................................... 102 5.2 Diplexer Using MSLDR and SSLDR.................................................................. 103 5.2.1 Analysis of MSLDR...................................................................................... 103 5.2.2 Analysis of SSLDR..................................................................................... 104 5.2.3 Dual-Band Bandpass Filter Design............................................................... 106 5.2.4 Development of Diplexer............................................................................... 112 5.2.5 Experimental Results and Discussion............................................................114 5.3 Conclusion.....................................................................................................114 Chapter 6 Conclusions and Recommendations......................................................116 6.1 Conclusions....................................................................................................116 6.2 Future Recommendations.....................................................................................117 Publications Bibliography指導教員 : 馬哲旺textapplication/pdfdoctoral thesi

Size Reduction and Harmonics Suppression in Microwave Power Dividers: A Comprehensive Review

In this paper, several types of microstrip power divider are studied and compared in terms of harmonics suppression and size reductions. The importance of this research lies in the fact that power dividers are critical components in various communication systems, and their performance directly affects the overall system efficiency. The conventional structure of the power divider has an acceptable performance at operating frequency in terms of excellent output ports isolation, low insertion loss, and high return loss, but occupies large size and passes unwanted signals at higher frequencies along with desired signal without any suppression. Harmonics are popular distortion and has different distortion impacts in many different facilities. Recently, several techniques are introduced to overcome these drawbacks. Applied open stubs, applied resonators, lumped reactive components such as capacitors and inductors, coupled lines, defected ground structure (DGS), and electronic band gaps are common methods, which are widely used to overcome these drawbacks. Finally, the study results show that the resonator-based power dividers and coupled-line-based power dividers have good performances in terms of size reduction and harmonic suppression but increase insertion loss parameter. Furthermore, the lumped reactive component-based power dividers and applied DGS and electromagnetic bandgap cells suppress unwanted harmonics, but they need extra process to fabrication, which is undesirable. Moreover, the open-stub-based power dividers have moderate performance with simple structure, but size reduction and harmonics suppression are not so superior in this method

Design of bandpass transversal filters employing a novel hybrid structure

A novel structure for the implementation of compact transversal bandpass filters is proposed in this paper. This new proposal consists of a hybrid structure, based on the combination of two different technologies: the waveguide and microstrip. It is shown that the novel hybrid microwave filter is able to implement both a second- and third-order filtering function with up to two or three transmission zeros, respectively. In this way, a practical implementation of a fully canonical transversal filter with a third degree response is for the first time directly achieved. In addition, the way to control the positions of transmission zeros with the new technology is treated in this paper. It is shown that symmetric or asymmetric responses and also filtering functions with a complex pair of transmission zeros can be easily obtained. To demonstrate the validity of this novel structure, several implementation examples are presented. A prototype has been designed, manufactured, and successfully tested, showing the practical validity of the new structure

Design of Dual-Bandpass Hybrid Waveguide-Microstrip Microwave Filters

A simple dual-bandpass filtering structure is pro- posed. The filter is implemented by means of a new hybrid waveguide­microstrip technology. The novelty of the structure is that it combines two standard printed microstrip coupled line resonators, with a resonance of the base waveguide cavity, to implement a dual-band operation. Important aspects about the filter design, useful for practical applications are treated. This includes a study on the maximum coupling that can be achieved to the cavity resonance, and guidelines to control the positions of the two passbands and the transmission zeros. Besides, an example has been designed, manufactured and tested. The measurements on the fabricated prototype have confirmed the validity of the new structure to perform dual-band operation.Ministerio de Educación y Ciencia, Ref. TEC2007-67630-C03-0

Wideband bandpass filters using a novel thick metallization technology

A new class of wideband bandpass filters based on using thick metallic bars as microwave resonators is presented in this work. These bars provide a series of advantages over fully planar printed technologies, including higher coupling levels between resonators, higher unloaded quality factors QU , and larger bandwidths implemented with compact structures. In comparison to dielectric and waveguide resonators filters, higher bandwidths together with lower weight and footprint reduction are achieved with the proposed thick bars technology. Moreover, thick bar resonators can easily be coupled to an additional resonance excited in a box used for shielding, allowing to realize transversal topologies able to implement transmission zeros at desired frequencies. To illustrate the capabilities of this technology, three microwave filters with different topologies have been designed. One of the designed filters has been manufactured and tested using copper bars inside an aluminum housing partially filled with Teflon. Measured data demonstrates a fractional bandwidth of FBW = 32%, spurious free range SFR > 50%, unloaded quality factor of QU = 1180, insertion losses over 0.16 dB and return losses over 20 dB, without requiring any post-tuning operation on the prototype. This result confirms the exciting performance of the proposed technology for wideband applications.This work was supported in part by the National Science Foundation with CAREER under Grant ECCS-1749177, in part by the Spanish Government, Ministerio de Educación, Cultura y Deporte under Grant FPU15/02883, and in part by the Ministerio de Economía y Competitividad through the Coordinated Project under Grant TEC2016-75934-C4-R and Grant PRX18/00092

Hybrid Microstrip Diplexer Design for Multi-band WiMAX Application in 2.3 and 3.5 GHz Bands

In this paper, a design of hybrid microstrip diplexer is proposed for multi-band Worldwide Interoperability for Microwave Access (WiMAX) application in 2.3 and 3.5 GHz bands. The diplexer consists of a combination of two different filter designs. These filters were designed based on microstripline coupling techniques in order to obtain minimum insertion losses and achieve the desired frequency bandwidth. Therefore, a coupled open loop ring resonator was chosen for the filter design in 2.3 GHz band and a folded coupled line resonator was chosen for the filter design in 3.5 GHz band. Then, these filters were combined with a ring manifold matching network to be a hybrid microstrip diplexer. Based on the results, good agreements were achieved between the simulation and measurement results in terms of insertion loss, return loss and bandwidth in the 2.3 and 3.5 GHz bands

Varactor-Tuned Dual-Mode Frequency Discriminator for Instantaneous Frequency Measurements

In this paper a novel varactor-tuned frequency discriminator that makes use of two tunable dual-mode microstrip resonators is demonstrated which doubles the discriminator tuning bandwidth. To prove its validity a prototype of the tunable dual-mode microstrip resonator is manufactured and the measured results are used to study the frequency discriminator response. This new approach can cover almost an octave of frequency range from 1.05 to 2 GHz with a sensitivity of 45 V/GHz and 21 V/GHz for the first and second mode, respectively.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech