Analysis of the Microstrip Disk Antenna Element,
Abstract
The circular microstrip antenna element is formed by a radiating disk closely spaced above a groundplane. It is modeled as a cylindrical cavity with magnetic walls that can be resonant in the TM modes. The far-fields and the radiation conductances for different mode structures have been calculated assuming a magnetic line current flowing around the perimeter of the disk. The directivity of the disk antenna excited in the dominant mode is between 4.8 dB and 9.9 dB, depending on the size. Losses, due to imperfect supporting dielectric and due to finite conductivity of the conductors, have been derived by means of a perturbation technique assuming small losses don't drastically change the fields from their loss-free case. Graphs are given for design purposes showing the input impedance, the Q-factor, and the radiation efficiency at resonance for different modes and spacings. The air-filled microstrip antenna has the highest efficiency and the broadest bandwidth for a given frequency. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1977
- Accession Number
- ADA051187
Entities
People
- Anders Derneryd
Organizations
- Rome Laboratory