Quality factor of helical coaxial cavity resonators with modulated radius

Giuseppe Salza, Jaione Galdeano, George Goussetis, Savvas A. Kosmopoulos, Marco Guglielmi

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)


This paper presents an analytical method for the estimation of the unloaded quality factor of helical coaxial cavity resonators in the case where the radius of the helix is modulated along the direction of its axis. The method exploits closed form expressions available for the electric and magnetic fields in the sheath helix. Appreciating that the ratio of stored versus dissipated power in each helix turn is independent of the field distribution within the resonator, the aforementioned closed form expressions readily enable the estimation of the Q-factor for arbitrary modulation of the helix radius. In earlier works, the reduction of the helical core towards the open end of the resonator has been proposed as means to increase the power handling capability. The work presented in this paper is a critical step towards optimizing the trade-off between Q-factor and power handling performance in helical coaxial cavity resonator filters.

Original languageEnglish
Title of host publication2014 44th European Microwave Conference (EuMC)
Number of pages4
ISBN (Print)9782874870354
Publication statusPublished - 15 Dec 2014
Event2014 44th European Microwave Conference - Rome, Italy
Duration: 6 Oct 20149 Oct 2014


Conference2014 44th European Microwave Conference
Abbreviated titleEuMC 2014
OtherHeld as Part of the 17th European Microwave Week, EuMW 2014


  • coaxial cavity resonators
  • filters
  • helical resonators
  • Q-factor
  • unloaded quality factor

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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