Low-pass filter with directional coupler and cellular phone
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsHiroshi Kushitani, Naoki Yuda, Yoshikuni Fujihashi, Koji Hashimoto
Life of this patent
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Abstract
An integrated component providing the function of both a conventional directional coupler and a low-pass filter having two attenuation poles at a specified frequency band without changing the line length. Stub lines are connected to both ends of a main transmission line of a directional coupler. A frequency of the attenuation poles is adjustable by characteristic impedance, terminating conditions, and line length of the stub lines.
Claims22
A low-pass filter with directional coupler comprising:
- a directional coupler having a main transmission line and a sub transmission line electromagnetically connected and disposed parallel to each other on the same dielectric board;
- and
- a stub line connected only to one end or respective stub lines connected only to each end of said main transmission line, each said stub line forming a series resonance circuit, and a resonance frequency of said series resonance circuit being adjustable by at least one of characteristic impedance, terminating conditions, and line length of said stub line.
A low-pass filter with directional coupler comprising:
- a directional coupler which comprises a main transmission line and a sub transmission line electromagnetically connected and disposed parallel to each other on the same dielectric board and
- a parallel circuit having a plurality of capacity components provided on at least one end of the main transmission line of said directional coupler, said capacity components including at least one stub line, said stub line forming a series resonance circuit, and a resonance frequency of said series resonance circuit being adjustable by at least one of characteristic impedance, terminating conditions, and line length of said stab line.
A low-pass filter with directional coupler comprising:
- a directional coupler which comprises a main transmission line and a sub transmission line electromagnetically connected and disposed in parallel with each other on the same dielectric board;
- a parallel circuit having a plurality of capacity components disposed on one end of said main transmission line of the directional coupler, said capacity components including at least one stub line;
- and
- at least one stab line disposed on the other end of said main transmission line of the directional coupler, said stub line having the line length which resonates with a specified frequency, said stub line forming a series resonance circuit, and a resonance frequency of said series resonance circuit being adjustable by at least one of characteristic impedance, terminating conditions, and line length of said stub line.
Dependencies are inferred from the claim text.