| Research Abstract |
A Design of passive components and integrated circuits consisting of (Hyper-)NRD guides ((H)NRD-guides) and/or rectangular waveguides
(a) The research derived dispersion characteristics of asymmetrical coupled-HNRD-guides consisting of two HNRD guides of difference cross sections arranged closely through the transverse resonance technique.
(b) Millimeter-wave directional couplers of 3 and 6 dB were designed by using the above asymmetrically coupled HNRD-guides at 60 GHz, and flat coupling properties were realized.
c The research designed two types of HNRD guide to rectangular waveguide transitions with a fractional bandwidth of about 10 percents.
(d) The research suggested the analytical and designing method of the (H)NRD and E-plane rectangular waveguide integrated structures on the basis of the transverse reosonance technique. In addition, the reseach realized a directional coupler of integrated HNRD-E-plane waveguide structure with a relative bandwidth of 10 percents.
(e) The research tr
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eated an asymmetrical coupled-HNRD-guide with difference groove dimensions by MoL (the method of lines) approach and realized a directional coupler with performance comparable to the above coupled-line couplers using this asymmetrical structure.
B. Design of E-plane waveguide components and integrated waveguide circuit
(a) Deign method of integrated E-plane multi-furcation power dividers was shown, and a three- and a four-way power dividers with a wide bandwidth over full X-band were successfully designed.
(b) The research exhibited the analytical method for radial E-plane waveguide multiports consisting of a coaxial cavity with n radially-coupled E-plane waveguides, applied the method to the optimum design of a waveguide-type rat-race, and demonstrated a good hybrid property comparable to that of an ideal 3/2-wavelength distributed rat-race by modifying cavity radius, port positions and Impedance steps inserted at each port.
(c) The research proposed a simple 3 dB hybrid consisting of an E-plane rectangular cavity with four diagonal coupling waveguides, and optimized the hybrid by using jointly with the E-plane planar-circuit approach, and the segmentation and desegmentation methods. In addition, a design tool for optimization of E-plane cavity-type hybrid was built up, and good hybrid properties were obtained.
(d) An eight-port hybrid constructed of four E-plane cavity-type hybrids were proposed, and its circuit configuration was optimized with the above approach. As a result, an eight-port hybrid having a bandwidth of 1.5 GHz was realized at K-band.
C. Design of H-plane waveguide components
(a) The research proposed compact H-plane multi-stepped and tapered directional couplers (short-slot hybrids) without complexity such as coupling apertures, septa, and tuning posts, and successfully designed various couplers with a broad bandwidth of 30 or more percents at X- and W-band by using the optimization tool on the basis of a multimode equivalent circuit model.
(b) An H-plane eight-port hybrid consisting of four above short-slot hybrids was suggested, and a circuit with a broad bandwidth of about 20 percents was designed.
D. Future subjects
(a) Development of a design tool inclusive of effect of conductor loss.
(b) Development of new guide structure for millimeter and sub-millimeter waves. Less
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