13 research outputs found
Towards measurable resilience: A novel framework tool for the assessment of resilience levels in slums
This paper investigates the need for a generic technique to be applied in the assessment of resilience-related projects in slums – particularly for localised infrastructure at a community level – and proposes a novel framework tool for this purpose. The paper outlines the development of the framework tool, as well as its pilot testing on the Kenya Slum Upgrading Programme in Kibera, Nairobi. The evaluation demonstrates an improvement in asset base, capacities and external resources for the community post intervention. The lack of land tenure was identified to be a key weakness and factor which impacted resilience of the local residents
Design and Synthesis of Parallel-Connected Dielectric Filter Using Chain-Function Polynomial
Design and synthesis of parallel connected die-lectric filters using chained function polynomials are pre-sented in this paper. This filter will offer reduced sensitivity to fabrication tolerance while preserving its return loss response within the desired bandwidth in comparison to traditional Chebyshev filters. A novel transfer function FN according to chained is derived for fourth and sixth-order filters and the synthesis technique is presented. To demon-strate the feasibility of this approach, the circuit simulation based on parallel connected topology is carried out in ADS while the design and simulation of the fourth-order filter in dielectric technology in HFSS. Considerable sensitivity analysis is conducted to prove a better fabrication toler-ance of the filter. In terms of implementation, this design technique will serve as a very useful mathematical tool for any filter design engineer
Design and Synthesis of Parallel-Connected Dielectric Filter Using Chain-Function Polynomial
Design and synthesis of parallel connected die-lectric filters using chained function polynomials are pre-sented in this paper. This filter will offer reduced sensitivity to fabrication tolerance while preserving its return loss response within the desired bandwidth in comparison to traditional Chebyshev filters. A novel transfer function FN according to chained is derived for fourth and sixth-order filters and the synthesis technique is presented. To demon-strate the feasibility of this approach, the circuit simulation based on parallel connected topology is carried out in ADS while the design and simulation of the fourth-order filter in dielectric technology in HFSS. Considerable sensitivity analysis is conducted to prove a better fabrication toler-ance of the filter. In terms of implementation, this design technique will serve as a very useful mathematical tool for any filter design engineer
Design of Compact Parallel-Connected Chained Function Filters
The design of compact parallel-connected chained function filters is presented in this paper. The proposed filters will offer reduced sensitivity to manufacturing tolerance within the specified bandwidth in comparison to conventional Chebyshev filters for C-band applications. A new filtering function according to a chained configuration is derived for fourth-order filters, and the synthesis procedures are presented. To demonstrate the feasibility of this approach, the circuit simulation based on parallel-connected topology is performed in an advanced design system, while the design and simulation of a fourth-order filter in dielectric technology are carried out in high-frequency simulation software. The prototype of fourth-order microstrip topology is fabricated using open-loop resonators. The overall circuit size of the filter is 2.5 cm × 4 cm. The achieved simulation and measured insertion/return loss are 0.409 dB/20 dB and 2.674 dB/18.074 dB, respectively. Extensive sensitivity analysis is conducted to prove the fabrication tolerance of the filter. The reduced sensitivity of the proposed filter to manufacturing tolerance is fully demonstrated using an open-loop microstrip technology, and its reliability is proven by theoretical analysis. The prototype results in this research are validated and agree with the theoretical results. In terms of implementation, this design technique will be a very useful mathematical tool for any filter design engineer
Design of Multi-Band Filters Using Parallel Connected Topology
This paper presents the design of multi-band filters using parallel connected topology. The resonator in each branch is the dual-mode resonator which provides two resonant modes per passband for miniaturization. The coupling values of the resonator are obtained by mapping the filtering function of the dual-mode resonator to the second order Chebyshev polynomial. The control of the filter parameters, such as pass-band bandwidths and band separation, is addressed. Dual-band and triple-band filter prototypes are designed and fabricated to validate the proposed concept. The measured results show good agreement with the simulations
Coupling matrix synthesis and design of a chained-function waveguide filter
This paper presents, for the first time, the coupling matrix synthesis for the application of a chained-function to waveguide filters. The realization of this filter is carried out by successively adding one resonator at a time by comparing the simulated responses of each stage with those obtained using the coupling matrix synthesized from the chained-function. A sixth-order chained-function waveguide bandpass filter centered at 28 GHz with a fractional bandwidth of 2% is demonstrated. The simulated S-parameter responses and the sensitivity analysis pertaining to the manufacturing errors is included. The chained-function waveguide has the lowest percentage changes in terms of the return loss performance given the same amount of distortion as compared with those of the Chebyshev response filters. This results in a lower sensitivity rate with respect to the manufacturing errors, leading to achieving a high-performance filter implementation with a minimum tuning effort
Design of Multi-Band Filters Using Parallel Connected Topology
This paper presents the design of multi-band filters using parallel connected topology. The resonator in each branch is the dual-mode resonator which provides two resonant modes per passband for miniaturization. The coupling values of the resonator are obtained by mapping the filtering function of the dual-mode resonator to the second order Chebyshev polynomial. The control of the filter parameters, such as pass-band bandwidths and band separation, is addressed. Dual-band and triple-band filter prototypes are designed and fabricated to validate the proposed concept. The measured results show good agreement with the simulations
A Modified Vector Fitting Technique to Extract Coupling Matrix from S-parameters
In this paper, a modified vector fitting technique to extract coupling matrix from S-parameters is introduced. This work allows designers to extract the coupling matrix of different or any pre-defined topologies from the simulated or measured S-parameter data. A study on vector fitting (VF) equations that can extract the rational polynomial of bandpass filter responses is carried out. The rational polynomials are formed by applying the VF process to S-parameter responses without having to remove the phase offset and de-embedding the transmission lines. The desired coupling matrix configuration is generated directly from the extracted polynomials using unconstrained and finitely bounded non-linear polynomials (NLP) optimization. Without the need for matrix transformation, the matrix elements are still able to show a one-to-one relationship in coupling values of resonators. Two bandpass filters are shown as examples to illustrate the performance of the new variation of VF