Compact hybrid microwave choke
AssigneePhilips Electronics North America Corporation
InventorJose M. Garcia
Life of this patent
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Abstract
A microwave choke is provided which includes a lumped-element capacitor, a lumped-element inductor and a transmission line.
Claims8
A microwave choke which is adapted for connection to a circuit which, at an operating frequency of f.sub.o, has a characteristic impedance Z.sub.o with a predetermined magnitude, said choke comprising, electrically connected in series:
- a. a lumped-element capacitor having a reactance X.sub.C which, at f.sub.o, is much smaller than the magnitude of the characteristic impedance Z.sub.o ;
- b. a lumped-element inductor having a resistance R.sub.L which is much smaller than the magnitude of the characteristic impedance Z.sub.o and having a reactance X.sub.L which, at f.sub.o, is much larger than the resistance R.sub.L and produces a phase shift .PHI..sub.L which is equivalent to an electrical length of .lambda..sub.L =N(.lambda..sub.o /4), where N is less than 1 and where .lambda..sub.o is the wavelength of signals propagating at f.sub.o ;
- and
- c. a transmission line which, at f.sub.o, has an electrical length substantially equal to .lambda..sub.o /4-.lambda..sub.L and has a characteristic impedance with a magnitude that is not substantially different from the magnitude of Z.sub.o.
A microwave choke disposed on a dielectric substrate supporting a conductive layer defining a ground plane, said choke being adapted for connection to a circuit which, at an operating frequency of f.sub.o, has a characteristic impedance Z.sub.o with a predetermined magnitude, said choke comprising, electrically connected in series:
- a. a lumped-element capacitor having a reactance X.sub.C which, at f.sub.o, is much smaller than the magnitude of the characteristic impedance Z.sub.o ;
- b. a lumped-element inductor having a resistance R.sub.L which is much smaller than the magnitude of the characteristic impedance Z.sub.o and having a reactance X.sub.L which, at f.sub.o, is much larger than the resistance R.sub.L and produces a phase shift .PHI..sub.L which is equivalent to an electrical length of .lambda..sub.L =N(.lambda..sub.o /4), where N is less than 1 and where .lambda..sub.o is the wavelength of signals propagating at f.sub.o ;
- and
- c. a transmission line which, at f.sub.o, has an electrical length substantially equal to .lambda..sub.o /4-.lambda..sub.L and has a characteristic impedance with a magnitude that is not substantially different from the magnitude of Z.sub.o.
A microwave circuit comprising a choke and a second circuit having a power-supply node, said second circuit, at an operating frequency of f.sub.o, having a characteristic impedance Z.sub.o with a predetermined magnitude, said choke comprising:
- a. a first node for electrical connection to a source of DC power;
- b. a second node for electrical connection to a reference potential;
- c. a third node for electrical connection to the power-supply node of the second circuit;
- d. a lumped-element capacitor having a first terminal electrically connected to the first node, having a second terminal electrically connected to the second node, and having a reactance X.sub.C which, at f.sub.o, is much smaller than the magnitude of the characteristic impedance Z.sub.o ;
- e. a lumped-element inductor and a transmission line which are electrically connected in series between the first node and the third node;
- said lumped-element inductor having a resistance R.sub.L which is much smaller than the magnitude of the characteristic impedance Z.sub.o and having a reactance X.sub.L which, at f.sub.o, is much larger than the resistance R.sub.L and produces a phase shift .PHI..sub.L which is equivalent to a transmission line electrical length of .lambda..sub.L =N(.lambda..sub.o /4), where N is less than 1 and where .lambda..sub.o is the wavelength of signals propagating at f.sub.o ;
- said transmission line, at f.sub.o, having an electrical length substantially equal to .lambda..sub.o /4-.lambda..sub.L and having a characteristic impedance with a magnitude that is not substantially different from the magnitude of Z.sub.o.
Dependencies are inferred from the claim text.