Analysis of an untilted wire-excited slot in the narrow wall of a rectangular waveguide by including the actual external structure

Author

Hirokawa, Jiro ; Manholm, Lars ; Kildal, Per-Simon

Author_Institution

Dept. of Electr. & Electron. Eng., Tokyo Inst. of Technol., Japan

Volume

45

Issue

6

fYear

1997

fDate

6/1/1997 12:00:00 AM

Firstpage

1038

Lastpage

1044

Abstract

The admittance of an untilted slot in the narrow wall of a rectangular waveguide is calculated by including the actual external structure. The slot is excited by two tilted thin wires inside the waveguide. The slot is also allowed to extend into the two broad walls of the waveguide to make it sufficiently long for resonance to occur. The external slot admittance is evaluated by using a spectrum of two-dimensional solutions, a method which can handle the arbitrary cross section of the external structure, The analysis predicts that if both the slot and the wires are tuned to resonance, the transmission coefficient gets constant phase over a wide-frequency band. The results also show that resonance can be obtained for any slot length by adjusting the wire length, and this relation between the lengths is presented. The distance between the slot and the wires needed to maximize the radiated power is also shown; some results are confirmed by measurements

Keywords

antenna feeds; electric admittance; rectangular waveguides; slot antennas; broad walls; cross section; external slot admittance; external structure; narrow wall; radiated power; rectangular waveguide; resonance; slot length; tilted thin wires; transmission coefficient; two-dimensional solutions; untilted wire-excited slot; wire length; Admittance; Antenna measurements; Dynamic range; Microwave antennas; Microwave technology; Polarization; Rectangular waveguides; Resonance; Slot antennas; Wires;

fLanguage

English

Journal_Title

Antennas and Propagation, IEEE Transactions on

Publisher

ieee

ISSN

0018-926X

Type

jour

DOI

10.1109/8.585753

Filename

585753