Abstract: A strip dual mode filter includes a strip line ring resonator having a uniform line impedance and an electric length equivalent to a wavelength of a microwave, an input terminal coupled to a point A of the ring resonator, a feed-back circuit connected to points C and D and arranged in a central hollow space of the ring resonator and an output terminal coupled to a point B of the ring resonator. The points A to D are spaced by a quarter-wave length of the microwave in that order. The microwave input to the point A is resonated in the ring resonator in a first mode and is input to the feed-back circuit from the point C. Therefore, a phase of the microwave shifts by a multiple of a half-wave length of the microwave, and the microwave is output to the point D. Thereafter, the microwave is resonated in the ring resonator in a second mode orthogonal to the first mode and is output from the point B to the output terminal.

Abstract: A strip dual mode loop resonator includes a loop-shaped strip line having a pair of straight strip lines arranged in parallel, an electric length of the loop-shaped strip line being equivalent to a wavelength of a microwave circulated in the loop-shaped strip line in two different directions according to a characteristic impedance of the loop-shaped strip line, and the straight strip lines being coupled to each other in electromagnetic coupling to change the characteristic impedance of the loop-shaped strip line. The microwave is transferred from an input strip line to the loop-shaped strip line through electromagnetic field induced by the microwave. Thereafter, the microwave is reflected in the straight strip lines of the loop-shaped strip line to produce reflected microwaves circulated in opposite directions. Thereafter, the reflected waves are resonated and filtered in dual mode in the loop-shaped strip line.

Abstract: A strip dual mode filter consists of a strip line ring resonator having an electric length equivalent to a resonance wavelength .lambda..sub.o for resonating microwaves at the resonance wavelength .lambda..sub.o according to a characteristic impedance thereof, an input coupling capacitor for transmitting the microwaves from an input terminal to a coupling point A of the ring resonator, an output coupling capacitor for outputting the microwaves resonated in the ring resonator from a coupling point B of the ring resonator to an output terminal, and a phase-shifting circuit connected to a coupling point C and a coupling point D of the ring resonator for changing the characteristic impedance of the ring resonator by shifting a phase of the microwave by a multiple of a half-wave length of the microwaves.

Abstract: A strip dual mode filter consists of a strip line ring resonator having an electric length equivalent to a resonance wavelength .lambda..sub.o for resonating microwaves at the resonance wavelength .lambda..sub.o according to a characteristic impedance thereof, an input coupling capacitor for transmitting the microwaves from an input terminal to a coupling point A of the ring resonator, an output coupling capacitor for outputting the microwaves resonated in the ring resonator from a coupling point B of the ring resonator to an output terminal, and a phase-shifting circuit connected to a coupling point C and a coupling point D of the ring resonator for changing the characteristic impedance of the ring resonator by shifting a phase of the microwave by a multiple of a half wavelength of the microwaves.

Abstract: A strip dual mode loop resonator includes loop-shaped strip line having a pair of straight strip lines arranged in parallel, an electric length of the loop-shaped strip line being equivalent to a wavelength of a microwave circulated in the loop-shaped strip line in two different directions according to a characteristic impedance of the loop-shaped strip line, and the straight strip lines being coupled to each other in electromagnetic coupling to change the characteristic impedance of the loop-shaped strip line. The microwave is transferred from an input strip line to the loop-shaped strip line through electromagnetic field induced by the microwave. Thereafter, the microwave is reflected in the straight strip lines of the loop-shaped strip line to produce reflected microwaves circulated in opposite directions. Thereafter, the reflected waves are resonated and filtered in dual mode in the loop-shaped strip line.

Abstract: A strip dual mode filter consists of a strip line ring resonator having an electric length equivalent to a resonance wavelength .lambda..sub.o for resonating microwaves at the resonance wavelength .lambda..sub.o according to a characteristic impedance thereof, an input coupling capacitor for transmitting the microwaves from an input terminal to a coupling point A of the ring resonator, an output coupling capacitor for outputting the microwaves resonated in the ring resonator from a coupling point B of the ring resonator to an output terminal, and a phase-shifting circuit connected to a coupling point C and a coupling point D of the ring resonator for changing the characteristic impedance of the ring resonator by shifting a phase of the microwave by a multiple of a half-wavelength of the microwaves.

Abstract: A strip dual mode filter consists of a strip line ring resonator having an electric length equivalent to a resonance wavelength .lambda..sub.o for resonating microwaves at the resonance wavelength .lambda..sub.o according to a characteristic impedance thereof, an input coupling capacitor for transmitting the microwaves from an input terminal to a coupling point A of the ring resonator, an output coupling capacitor for outputting the microwaves resonated in the ring resonator from a coupling point B of the ring resonator to an output terminal, and a phase-shifting circuit connected to a coupling point C and a coupling point D of the ring resonator for changing the characteristic impedance of the ring resonator by shifting a phase of the microwave by a multiple of a half-wave length of the microwaves.

Abstract: A strip dual mode loop resonator includes a loop-shaped strip line having a pair of straight strip lines arranged in parallel, an electric length of the loop-shaped strip line being equivalent to a wavelength of a microwave circulated in the loop-shaped strip line in two different directions according to a characteristic impedance of the loop-shaped strip line, and the straight strip lines being coupled to each other in electromagnetic coupling to change the characteristic impedance of the loop-shaped strip line. The microwave is transferred from an input strip line to the loop-shaped strip line through electromagnetic field induced by the microwave. Thereafter, the microwave is reflected in the straight strip lines of the loop-shaped strip line to produce reflected microwaves circulated in opposite directions. Thereafter, the reflected waves are resonated and filtered in dual mode in the loop-shaped strip line.