Rafik Hariri philanthropic and developmental contributions are countless. The most remarkable being the multifaceted support to educate more than 36,000 Lebanese university students within Lebanon, and beyond.
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A STUDY OF MULTI-PORT NONRECIPROCAL JUNCTION COMPONENTS
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Assaad M. BORJAK
|
Univ. |
Manchester I.S.T. |
Spec. |
Communication Engineering |
Deg. |
Year |
#Pages |
|
Ph.D. |
1993 |
206 |
To enable the scattering matrix for any specified three‑port and four‑port intrinsic planar structure to be computed as a function of frequency, a user-friendly Computer‑Aided Design package for novel microwave components is built. The theory of simple and composite components is extended and computer programs are written . Only circulators are dealt with in this thesis. The method for the design of circulators introduced by Wu and Rosenbaum in 1974 [12] is followed where highest priority is given to using the main mode of circulation and single circulation frequency operation.
The conventional Y‑disk circulator is treated for high frequency operations using both Modes I and 2 a compact 6.34 GHz Y‑disk circulator is obtained with 50 Ω out‑put impedance. A novel W circulator based on a three‑port ferrite disk having two ports positioned 60o from a middle port is proposed and explored. Based on M-type hexagonal Ferrites, self‑biased Y‑disk circulators operating in the below resonance regime are compared with the conventional Y‑disk circulator.
A second type, based on ferrite rings, called the Y‑ring circulator, is treated. By assuming that the inner circumference exhibits a magnetic wall (MW), this obviates the need for transformers. Then, by considering the dielectric (air)inside the inner hole a new DF Y‑ring circulator is obtained.
Finally, four‑port ferrite disk circulators are discussed. Using the newly derived circulation conditions and with only the two adjustments made in the Y-Disk circulator [6], perfect circulation in such circulators is proved to be impossible. An attempt to design such circulators is made. A narrow bandwidth X‑disk circulator is obtained.
