171 research outputs found
Dual Mode Suspended Substrate Stripline (SSS) Filter
Evolution of wireless communication systems towards high flexibility, low cost and high efficiency leads to tremendous activity in the area of microwave
filters. In an RF front-end of a cellular radio base station, signals are being transmitted and received simultaneously. In the receive band, there are chances
of intermodulation products from the power amplifier being fed to the receiver,thus the transmit filter must have a very high level of signal rejection. Furthermore, the transmit filter must also have low passband insertion loss since it impacts the power transmitted and the overall transmit system efficiency. Recently, filters with dual-mode operation were being investigated due to their ability to produce two degenerate modes using a single physical structure; therefore, the size and cost of the filter can be reduced without compromising
any figure-of-merits. A dual mode suspended substrate stripline filter is presented in this thesis. These filters enable achieving low insertion loss, high Q, high selectivity and good spurious response. Initially, a dual mode ring resonator structure is investigated using suspended substrate stripline technology. This technology is used due to its advantages which are comparable to microstrip or any other planar transmission lines. The HFSS three dimensional finite element method (FEM) is used to evaluate the resonant frequency, quality factor and the first harmonics.A second order suspended substrate stripline filter was designed with capacitive coupled input and output feeding method. The input and output feed were positioned 90 degree from each other while a notch was used in this filter to couple two degenerate modes which also control the bandwidth of the filter. A high performance Generalized Chebychev filter was designed to meet the stringent electrical requirement in the RF front-end of a cellular radio base station. With this fourth order filter, four finite frequency transmission zeros were achieved due to phase cancellation between two paths which results in high
selectivity filter response. Metal tuning screws were added to improve any practical imperfections. Finally an asymmetrical Generalized Chebychev filter was designed with real frequency transmission zeros positioned on one side of the passband. With this design, the aim of achieving higher selectivity filter response above the passband was demonstrated
Folded waveguide resonator filter for communication and radar systems
In this thesis, a primary investigation into developing a compact and low-loss bandpass
filter, using novel folded waveguide resonators with a footprint reduction, has been
addressed. A slot coupling between adjacent resonators is introduced, which is
characterized by using full-wave EM simulations and verified experimentally. Two
designs of 2-pole folded waveguide resonator filters of this type have been considered,
fabricated and tested. In this thesis, an even more compact FWG resonator filter using a
novel slot technique is reported. The attainable size reduction is about 50%, and the
filter design is based on theoretical and full-wave electromagnetic (EM) simulations.
Based on FWG structure, two types of folded waveguide resonators have been studied
and considered the half-wavelength resonator and the quarter-wavelength resonator.
Moreover, both structures for the realization of microwave cavities with high-Q, with
the result of a high spurious free range and reduced footprint, have been evaluated.
Furthermore, a novel folded waveguide resonator with about a 75 % reduction of the
volume from the conventional size has been described. For comparison, two types of
folded waveguide resonators have been studied, i.e. the quarter-wavelength resonator of
square shape and the newly proposed triangular shape. In addition, a demonstration of a
filter application for miniature triangular folded waveguide resonators has been
designed and simulated using an EM simulator.
In addition, numbers of experiments have been conducted to develop cavity FWG and
Substrate Integrated folded waveguide SIFW resonator filters using a folded structure,
which is the main aim of this thesis. Furthermore, this thesis deals with the simulation
and implementation for many designs and topologies of FWG and SIFW resonator
filters and their frequency response. Simulation and experimental results were presented
to validate the design and to show the advantages of these types of filters. In addition, a
new type of filter with a compact multi-layer structure and low loss is attractive for
implementation with advanced device technologies, such as micromachining, LTCC
and LCP technologies
Multi mode Resonator based Concurrent Triple band Band pass Filter with Six Transmission Zeros for Defence Intelligent Transportation Systems Application
A compact and highly selective triple-band bandpass filter (BPF) is designed and presented in this paper. Proposed filter offers low insertion loss, and passband characteristics is achieved by using two coupled MMR multi-mode resonators (MMR1 and MMR2) and an inverted T and circular shape MMRs. The filter operates at frequency 2.43 GHz (Vehicular Communication), 5.91 GHz (ITS band), and 8.86 GHz (satellite communication band). The simulation and measurement results show a minimum insertion loss of 1.6 dB, 0.73 dB, and 2.8 dB for triple-band BPF. The return loss is found to be greater than 13.06 dB, 28.6 dB, and 21.55 dB. It is noted that measurement results are in accordance with the result of electromagnetic simulation. Desired triple-band multi-mode resonators (MMRs) filter characteristics are achieved with six transmission zeroes (TZs). The filter comprises of MMRs which provide small size and control over the spurious frequency. By using a parallel-coupled microstrip line, the first and third passbands are realised. Whereas by using an end-coupled microstrip line, the second passband is recognised. At the input and output ports, the resonator coupling technique is used. By using the anti-parallel microstrip line arrangement, the transmission zero is acquired. The dimensions of the designed filter are 25×16 mm 2
Planar microwave filters with electronically tunability and other novel configurations
In order to meet the increasing demands of advance wireless communications and
radar systems, several novel types of bandpass filters and bandstop filters have been
developed in this thesis.
A new type of varactor-tuned dual-mode bandpass filters have been presented to
achieve a nearly constant absolute bandwidth over a wide tuning range by using a single
DC bias circuit. Since the two operating modes (i.e., the odd and even modes) in a dualmode
microstrip open-loop resonator do not couple to each other, tuning the passband
frequency is accomplished by merely changing the two modal frequencies
proportionally. Design equations and procedures are derived, and two two-pole tunable
bandpass filters and a four-pole tunable bandpass filter of this type are demonstrated
experimentally.
Miniature microstrip doublet dual-mode filters that exhibit quasi-elliptic function
response without using any cross coupling have been developed. It shows that a single
two-pole filter or the doublet can produce two transmission zeros resulting from a
double behaviour of the dual-mode resonator of this type. Electromagnetic (EM)
simulation and experiment results of the proposed filters are described.
Parallel feed configuration of a microstrip quasi-elliptic function bandpass filter
has been built with a pair of open-loop dual-mode resonators. By employing this new
coupling scheme, a novel filter topology with three-pole quasi-elliptic function
frequency response can be obtained, leading to good passband performance, such as low
insertion loss and good matching at the mid-band of passband. A designed three-pole
bandpass filter of this type is demonstrated experimentally.
A new class of dual-band filters based on non-degenerate dual-mode microstrip
slow-wave open-loop resonators, which support two non-degenerate modes that do not
couple, have been introduced. Different feed schemes that affect the filtering
characteristics are investigated. Examples of dual-band filters of this type are described
with simulation and experiment results.
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In order to achieve a wide spurious-free upper passband, a novel design of
bandstop filter with cancellation of first spurious mode by using coupled three-section
step impedance resonators (SIRs) has been developed. This cancellation occurs when
two transmission poles coincide with the first spurious mode (transmission zero) by
properly choosing the step impedance ratio and the gap between the SIR and the main
transmission line. A stripline bandstop filter and a microstrip bandstop filter of this type
are designed, fabricated and tested. As a preliminary investigation, the microstrip filter
is tuned electronically using ferroelectric thin film varactors
Stripline multilayer devices based on Complementary Split Ring Resonators
A new analytic design for multilayer stripline devices in planar circuit technology is presented. The Complementary Split Ring Resonator (CSRR) is used as a sub-wavelength resonant particle, which provides high-Q resonances in a compact size. The electromagnetic field distribution achieved along the stripline enables enhanced excitation of the resonators. An optimal solution for multilayer power dividers is presented, in a configuration in which each output is obtained in different layers and also in a different layer than the input line. The solution is expanded to design different devices, such as diplexers, resonators, and multi-frequency resonators, leading to vertical filters. As the resonances are achieved by stacking resonators, the effective circuit footprint is very compact. The proposed devices can be implemented in a volumetric chip fashion, allowing integration with planar transmission line circuits and flexible output connection placement. A complete analysis of the different devices is proposed, extracting and verifying their equivalent circuit models.This work was supported by Ministerio de Ciencia, Innovación y Universidades, Gobierno de España (Agencia Estatal de Investigación, Fondo Europeo de Desarrollo Regional -FEDER-, European Union) under the research grant RTI2018-095499-B-C31 IoTrain
Novel Topologies Based Rf Filtering Components And Methodologies For Wireless Communication System
Driven by the rapid progress of wireless communication technology in the past several decades, multiple generations of cellular technologies have been developed, deployed, and adopted to provide more convenient communication services to users. Nowadays, the personal hand-held devices, supporting multiple wireless standards, have been a multimedia terminal encompassing elements and functions such as video callers, Internet connectivity, home appliances remote controller, GPS, TV reception, and beyond. In order to accommodate a variety of wireless standards in a single device without imposing a substantial increase in cost and size, current and future RF transceiver front-ends should be designed with more attention. The main objective of this dissertation is to study new design topologies and implement a series of high performance RF filtering components which play critical roles in miniaturized RF transceivers supporting multiple wireless standards. A compact dual-band filter with high selectivity and wide rejection band, a filtering Wilkinson power divider, and balanced filters with fixed/reconfigurable center frequencies are proposed and successfully developed. In addition, an equation-based methodology is also first proposed and fully investigated to r
Self-packaged miniature microwave filters based on multilayer liquid crystal polymer technology
The following thesis is concerned with the development of fabrication techniques
and novel designs for self-packaged, multilayer circuits using liquid crystal polymer
(LCP) materials exclusively, given the favourable characteristics this material has
for microwave circuits.
Fabrication techniques are aimed at the production of miniature, low-profile filters.
Advanced techniques for production of interlayer via connections are investigated
and new methods proposed, with special attention at the lamination process and
production of vertical, inter-layer transitions. Results obtained demonstrate the
fabrication process is reliable for producing multilayer filters, with up to four metal
layers, and via transitions in the region of 0.2 mm diameter.
The fabrication process has been developed during this work is applied to novel filter
designs, covering dual-band filters and lowpass filters. A new structure for dual-
band filter is proposed, using folded multimode resonators (FMSIR). This structure
is validated through the fabrication of two different filters with passbands 1.2/2.4
GHz, and 2.4/5 GHz, showing deep off-band rejection.
Low pass structure covered in this thesis is based on the principle of destructive
interference and aims at low insertion loss and out-of-band rejection higher than
40 dB. Fabricated samples validate the design showing a rejection in the region of
42 dB, with a cuto frequency of 3 GHz. Its small footprint and low insertion loss
allows this type of lters to be used as cleanup filters. All the designs covered in
this work are simulated using CAD tools and then validated by measurements on
fabricated samples
Compact Stepped Impedance Resonator Bandpass Filter with Tunable Transmission Zeros
This paper proposes a compact microstrip bandpass filter (BPF) with tunable transmission zeros, narrow bandwidth and low insertion loss. A λ/4 stepped impedance resonator (SIR) with two additional via holes has been adopted to obtain a compact size and a pair of transmission zero (TZ). Furthermore, three techniques have been developed to create a pair of controllable transmission zeros on both side of each passband. The TZ can be controlled by adjusting either magnetic or electric coupling. The measured return losses and insertion loss is larger than 18 dB and 2.2 dB respectively. The overall size of the proposed design filter is 5.3mm x 5.5mm without considering the feeding lines
Development of waveguide filter structures for wireless and satellite communications
This thesis explores the possibilities of the design and realization of compact conventional and substrate integrated waveguide structures with improved performance taking advantage of recent cross-coupled resonator filters theory achievements such as the modular filter design approach using non-resonating nodes and inline extracted pole filters. Therefore, the core of the thesis presents the following stages of work:
-- Solution of electromagnetic problem for wave propagation in rectangular
waveguide structures; overview of substrate integrated waveguides.
-- Review of available design procedures for cross-coupled resonator filters;
realization of coupling matrix synthesis methods by optimization.
-- Investigation of the possibility to implement filtering modules using E-plane metallo-dielectric inserts in conventional rectangular waveguides. Application of the modules in configurations of bandpass and dual-band filters. Experimental
verification of the filters.
-- Implementation of inline extracted pole filters using E-plane inserts in
rectangular waveguides. Use of generalized coupling coefficients concept for
individual or coupled extracted pole sections. Development of new extracted
pole sections. Application of the sections in the design of compact cross-coupled filters with improved stopband performance.
-- Application of the techniques developed for conventional rectangular
waveguides to substrate integrated technology. Development of a new negative
coupling structure for folded substrate integrated resonators. Design of improved modular and extracted pole filters using substrate integrated waveguides
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