The Windows ® program for designing helical-resonator-based filters

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Helical is one of the programs included on the Bonus CD accompanying the 2008 ARRL Handbook

This is a graphics-intensive bandpass filter design and analysis program based on the helical resonator. Here are the highlights of this program: The program designs bandpass filters with a selection of the order from 2 to 12. Center frequency, bandwidth, and passband ripple are all adjustable. The ripple value may be set to zero for a Butterworth response. The dimensions of the individual resonators are set by specifying an impedance value. Then the actual terminating impedances are separately chosen. Analysis is based on an equivalent circuit using capacitive input, interstage and output coupling. Analysis is delivered in both tabular and graphical form and includes transmission, return loss, phase, envelope delay and input impedance with its angle. The dimensions of the resonator(s) delivered by the program are shown in graphical form. References: Coaxial Resonators with Helical Inner Conductor W. W. Macalpine Proceedings of the I.R.E., December 1959 Need A Helical Filter? Lee R. Watkins RF Design, May 1961 Realization of a Filter With Helical Components A. I. Zverev and H. J. Blinchikoff I.R.E. Transactions on Component Parts Volume CP8, September 1961 Design Of A New, Low-Cost Helical-Resonator Filter Solomon I. Hecht Microwaves, February 1966 Helical Filters (Chapter 9) A. I. Zverev Handbook of Filter Synthesis John Wiley & Sons, 1967 Library of Congress Card Number 67-17352 Helical-Resonator Filter Design, Vincent G. Heesen RF Design, July 1985