Patent ID: 6140892
Filing Date: 2000-10-31
Classification: H01P

Abstract:
A distributed constant circuit comprising:a first distributed constant transmission line;a first capacitor;a second distributed constant transmission line connected in series with said first capacitor;a second capacitor; anda third distributed constant transmission line connected in series with said second capacitor, said distributed constant circuit having a structure in which one end of said first distributed constant transmission line is connected to a predetermined reference potential through a series connection between said first capacitor and said second distributed constant transmission line, and the other end of said first distributed constant transmission line is connected to said reference potential through a series connection between said second capacitor and said third distributed constant transmission line,the other end of said first distributed constant transmission line being in a substantially open state with respect to a first frequency and being in a substantially short-circuited state with respect to a second frequency different from said first frequency when the one end of said first distributed constant transmission line is brought into a grounded state in an alternating current manner, the characteristic impedance Z.sub.a of said first distributed constant transmission line, the length L.sub.a of said first distributed constant transmission line, the characteristic impedance Z.sub.b of said second and third distributed constant transmission lines, the length L.sub.b of said second and third distributed constant transmission lines, the capacitance value C of said first and second capacitors, a first frequency f.sub.1, a wavelength .lambda..sub.1 corresponding to said first frequency, a second frequency f.sub.2, and a wavelength .lambda..sub.2 corresponding to said second frequency satisfy relations expressed by equations (1), (2) and (3): ##EQU39##