445 research outputs found
Substrate Integrated Waveguide Filters Based on Even- And Odd-Mode Predistortion Technique
Novel techniques for the design of predistorted
Substrate Integrated Waveguide (SIW)
bandpass and bandstop filter are presented.
The techniques allow for the realization of lossy
filters with ideal lossless transmission and
reflection response, offset by a constant amount.
Two prototype third-degree Chebyshev bandpass
and Inverse Chebyshev bandstop filters are
proposed and designed. The two SIW filters
having the same center frequency of 6.5 GHz
and bandwidth of 125 MHz are implemented
on RT/Duroid 4350 substrate with thickness of
0.508 mm. Experimental results show excellent
agreement with simulated performance. These
new class of filters would be useful in microwave
systems where the increased insertion loss can
be tolerated, such as in a satellite IMUX
The design and fabrication of miniature microwave bandpass filters using multilayer liquid crystal polymer technology
This thesis presents the design and fabrication techniques for miniature microwave
bandpass filters using multilayer liquid crystal polymer (LCP) technology.
As a multilayer technology for microwave devices, LCP is of low cost and light weight. It
also has excellent electrical properties across a wide frequency range. These characteristics
make it promising for the development of next generation microwave devices for
applications across commercial, defence and civil sectors. However, very limited work has
been found in the open literature to apply this technology to the design of miniature
bandpass filters, especially at low microwave frequencies. In addition, the reported work
shows lack of fabrication techniques, which limits the size reduction of multilayer LCP
devices.
To address these problems, this thesis develops advanced fabrication techniques for
sophisticated LCP structures, such as multilayer capacitors, via connections and cavities.
These techniques are then used to support the design of novel miniature bandpass filters for
wideband and narrowband applications. For the design of miniature wideband bandpass
filters, a cascaded approach, which combines highpass and lowpass filters, is presented first
to provide a flexible design solution. This is followed by another novel ultra-wideband
bandpass filter which produces extra transmission zeroes with minimum number of
elements. It does not only have high performance but also a compact structure for high
yield fabrication. For narrowband applications, two types of advanced coupled-resonator
filters are developed. One type produces a very good selectivity at the upper passband edge,
and its spurious-free stopband is extremely wide and of high interference attenuation. The
other type, based on novel mixed-couplings approaches developed in this thesis, provides a
solution to produce almost the same response as the coupling matrix prototype. This type is
used to generate arbitrarily-located transmission zeroes.
All designs presented in this thesis are simulated using CAD design tools and then
validated by measurements of fabricated samples. Good agreements between simulations
and measurements are shown in the thesis
Fir filter design for area efficient implementation /
In this dissertation, a variable precision algorithm based on sensitivity analysis is proposed for reducing the wordlength of the coefficients and/or the number of nonzero bits of the coefficients to reduce the complexity required in the implementation. Further space savings is possible if the proposed algorithm is associated with our optimal structures and derived scaling algorithm. We also propose a structure to synthesize FIR filters using the improved prefilter equalizer structure with arbitrary bandwidth, and our proposed filter structure reduces the area required. Our improved design is targeted at improving the prefilters based on interpolated FIR filter and frequency masking design and aims to provide a sharp transition-band as well as increasing the stopband attenuation. We use an equalizer designed to compensate the prefilter performance. In this dissertation, we propose a systematic procedure for designing FIR filters implementations. Our method yields a good design with low coefficient sensitivity and small order while satisfying design specifications. The resulting hardware implementation is suitable for use in custom hardware such as VLSI and Field Programmable Gate Arrays (FPGAs).FIR filters are preferred for many Digital Signal Processing applications as they have several advantages over IIR filters such as the possibility of exact linear phase, shorter required wordlength and guaranteed stability. However, FIR filter applications impose several challenges on the implementations of the systems, especially in demanding considerably more arithmetic operations and hardware components. This dissertation focuses on the design and implementation of FIR filters in hardware to reduce the space required without loss of performance
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