M-Shaped Dielectric Phase Shifter for Beam-Steerable Base-Station Antenna

Kengo NISHIMOTO  Takeshi OSHIMA  Toru FUKASAWA  Hiroaki MIYASHITA  Yoshihiko KONISHI  Manabu KURIHARA  Yoshiyuki CHATANI  

IEICE TRANSACTIONS on Communications   Vol.E96-B   No.8   pp.2095-2101
Publication Date: 2013/08/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E96.B.2095
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Antennas and Propagation
phase shifter,  dielectric,  M-shaped,  base-station antenna,  

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We propose a simple and small phase shifter for a beam-steerable base-station antenna. This phase shifter has no metallic heterojunction, and the phase shift is controlled by moving an M-shaped dielectric plate between the strip conductor and the ground plane of a strip line. We derive a design equation from the condition that at the center frequency f0, the reflection coefficient = 0. In this phase shifter, the reflection coefficient becomes minimum at f0 regardless of the movement distance, r, of the dielectric plate, and the relationship between the phase shift and r is linear. These characteristics are verified by performing simulations and measurements. The size of the M-shaped dielectric phase shifter is 0.27λ00.12λ0, where λ0 is the free-space wavelength at f0. The insertion loss is smaller than about 0.2 dB within a fractional bandwidth of 10%, and the phase shift can vary from 0 to about 80 degrees.