James Chu
Ayushman Raghuvanshi received his B.Tech. degree in electrical engineering from National Institute of Technology Rourkela. He is an analog design intern with Texas Instruments. He is also an intern with the Defense Research and Development Organization.
Dr. Rakesh Sinha received his B.Tech. degree in electronics and communication engineering from Kalyani Government Engineering College, Kalyani, India, in 2008, and his M.Tech. and Ph.D. degrees in RF and microwave engineering from the Indian Institute of Technology, Kharagpur, India, in 2011 and 2016, respectively. Sinha has a number of IEEE publications on phase-shifting [1] and multisection matching networks with desired phase shifts [2].
This excellent article on microwave filter design, which can be accessed on IEEE TechRxiv at https://tinyurl.com/26ut7ffd, is designed to help many engineering college students understand the mechanism behind filter design and realization, especially in the case of analog and microwave filters. There are many filter design software packages, but one way or another, they are not fit to the low-cost tool for filter design. This article introduces the authors’ developed Microwave Filter Design Kit to fill in this gap and to provide solutions based on various polynomials, along with microwave implementation of the filters. The package includes the scattering parameters of the filter for extended analysis. The simple user interface makes it easy for new students to try filter synthesis themselves. It establishes a clear link between filter design components and the mathematical model of the filter, making it a crucial aid for instructing undergraduate students.
The design kit works on the principle of insertion loss: it takes specifications from the user through the simple user interface and uses these specifications to design a normalized unit source impedance and unit cutoff frequency of a low-pass filter prototype. It develops the prototype from two available polynomials: Butterworth and Chebyshev. The Butterworth polynomial has a maximally flat response in the passband, whereas the Chebyshev one provides control over passband ripples. After designing a prototype filter, it scales the element values to match the source impedance and transforms the prototype elements to achieve the desired filter type based on user selection.
The authors explain two types of filters topologies: lumped filter and distributed filter design, and the applications of both. In the article, the authors gave many examples on different type of filters, including the circuit design, analysis, and simulation, by following their Microwave Filter Design Kit procedure.
This design kit is a multifunctional package with enormous potential. It automates the filter design and realization process, developing various implementations for high-frequency applications. It complements the design of projects by providing filters of precise specifications. Moreover, it links the mathematical model and an actual filter, helping engineering students and academicians with the filter design methodology and giving them the freedom to design filters easily. This kit can be downloaded by visiting the IEEE DataPort at https://ieee-dataport.org/documents/microwave-filter-design-kit. The author, Sinha, has posted many very interesting and short educational articles on LinkedIn, and readers can contact him through his posts there.
In conclusion, this article gave a very good explanation of how the Microwave Filter Design Kit works. Based on this article, it seems that this design kit is an alternative way for engineering college students to use this CAD software program to learn microwave filter design theory and practice without breaking a school’s bank account.
[1] R. Sinha and A. De, “Synthesis of multiport networks using port decomposition technique and its applications,” IEEE Trans. Microw. Theory Techn., vol. 64, no. 4, pp. 1228–1244, Apr. 2016, doi: 10.1109/TMTT.2016.2532868.
[2] R. Sinha, “Computer-aided design of multisection matching networks with desired phase-shift,” IEEE Trans. Circuits Syst., II, Exp. Briefs, vol. 69, no. 12, pp. 5074–5078, Dec. 2022, doi: 10.1109/TCSII.2022.3201114.
Digital Object Identifier 10.1109/MMM.2022.3233477