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US 5,477,200 AGranted
Variable attenuator
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorTomohiko Ono
Life of this patent
Estimating the term…
Abstract
A current bias-type variable attenuator. Two PIN diodes are disposed in series to each other and in the forward direction on a bias current path. When a bias voltage is applied to a bias terminal, d.c. current flows in the order of a combination output port, an in-phase output port, a first PIN diode, an input port, a 900.degree.--delayed phase output port, and a second PIN diode, or in the order of the combination output port, the in-phase output port, the first PIN diode, the second PIN diode, the 900.degree.--delayed phase output port, and the input port. Since d.c. current flowing through the first PIN diode and d.c. current flowing through the second PIN diode have an equal value, an RF resistance of the first PIN diode and that of the second PIN diode are balanced.
Claims42
A variable attenuator comprising:
- a multiport coupler having a first port, a second port, a third port, and a fourth port, the second, third, and fourth ports being responsive to the first port so that when a first radio frequency signal is inputted in the first port, a second radio frequency signal being in-phase with the first radio frequency signal appears at the second port, a third radio frequency signal being in 90.degree.--delayed phase with the first radio frequency signal appears at the third port, and a fourth radio frequency signal appears at the fourth port, the fourth radio frequency signal having a first signal portion in 90.degree.--delayed phase with the second radio frequency signal and a second signal portion in opposite phase with the third radio frequency signal;
- a single d.c. current path through which a supplied d.c. current flows according to a required attenuation;
- and
- first and second variable radio frequency resistive elements which are disposed on said d.c. current path, that make up at least a part of a termination impedance of the second and third ports, respectively, and that produce resistance of a value corresponding to a value of the supplied d.c. current, the fourth port being disposed on said d.c. current path.
1 more element
A variable attenuator comprising:
- a multiport coupler having a first port, a second port, a third port, and a fourth port, the second, third, and fourth ports being responsive to the first port so that when a first radio frequency signal is inputted in the first port, a second radio frequency signal being in-phase with the first radio frequency signal appears at the second port, a third radio frequency signal being in 990.degree.--delayed phase with the first radio frequency signal appears at the third port, and a fourth radio frequency signal appears at the fourth port, the fourth radio frequency signal having a first signal portion in 90.degree.--delayed phase with the second radio frequency signal and a second signal portion in opposite phase with the third radio frequency signal;
- a single d.c. current path through which a supplied d.c. current flows according to a required attenuation;
- and
- first and second variable radio frequency resistive elements which are disposed on said d.c. current path, that make up at least a part of a termination impedance of the second and third ports, respectively, and that produce resistance of a value corresponding to a value of the supplied d.c. current;
- wherein
- the first port is isolated from the second port, and the third port is isolated from the fourth port in terms of direct current, respectively;
- said d.c. current path being provided with the following in a direction of said supplied d.c. current,
- a terminal for supplying the supplied d.c. current,
- a first circuit for making a d.c. connection of the terminal and the fourth port while isolating the fourth radio frequency signal,
- the first variable radio frequency resistive element which is coupled to the second port,
- a second circuit which makes d.c. isolation of the first and second variable radio frequency resistive elements and a ground while making a radio frequency connection, and also makes d.c. connection of the first variable radio frequency resistive element and the second variable radio frequency resistive element while isolating a radio frequency signal,
- the second variable radio frequency resistive element which is coupled to the third port, and
- a third circuit for making d.c. connection of the first port and the ground while isolating the first radio frequency signal.
10 more elements
A variable attenuator comprising:
- a multiport coupler having a first port, a second port, a third port, and a fourth port, the second, third, and fourth ports being responsive to the first port so that when a first radio frequency signal is inputted in the first port, a second radio frequency signal being in-phase with the first radio frequency signal appears at the second port, a third radio frequency signal being in 90.degree.--delayed phase with the first radio frequency signal appears at the third port, and a fourth radio frequency signal appears at the fourth port, the fourth radio frequency signal having a first signal portion in 90.degree.--delayed phase with the second radio frequency signal and a second signal portion in opposite phase with the third radio frequency signal;
- a single d.c. current path through which a supplied d.c. current flows according to a required attenuation;
- and
- first and second variable radio frequency resistive elements which are disposed on said d.c. current path, that make up at least a part of a termination impedance of the second and third ports, respectively, and that produce resistance of a value corresponding to a value of the supplied d.c. current;
- wherein
- the first port is isolated from the second port, and the third port is isolated from the fourth port in terms of direct current, respectively,
- said d.c. current path being provided with the following in a direction of said supplied d.c. current:
- a terminal for supplying the supplied d.c. current,
- a first circuit for making a d.c. connection of the terminal and the fourth port while isolating the fourth radio frequency signal,
- the first variable radio frequency resistive element which is coupled to the second port,
- a second circuit which makes a radio frequency connection of the first variable radio frequency resistive element and a ground while making d.c. isolation and makes a d.c. connection of the first variable radio frequency resistive element and the first port while isolating the second radio frequency signal,
- the second variable radio frequency resistive element which is coupled to the third port, and
- a third circuit for making a d.c. connection of the second variable radio frequency resistive element and the ground while making d.c. isolation of the second variable radio frequency resistive element and the terminal.
10 more elements
A variable attenuator comprising:
- a multiport coupler having a first port, a second port, a third port, and a fourth port, the second, third, and fourth ports being responsive to the first port so that when a first radio frequency signal is inputted in the first port, a second radio frequency signal being in-phase with the first radio frequency signal appears at the second port, a third radio frequency signal being in 90.degree.--delayed phase with the first radio frequency signal appears at the third port, and a fourth radio frequency signal appears at the fourth port, the fourth radio frequency signal having a first signal portion in 90.degree.--delayed phase with the second radio frequency signal and a second signal portion in opposite phase with the third radio frequency signal;
- a single d.c. current path through which a supplied d.c. current flows according to a required attenuation;
- and
- first and second variable radio frequency resistive elements which are disposed on said d.c. current path, that make up at least a part of a termination impedance of the second and third ports, respectively, and that produce resistance of a value corresponding to a value of the supplied d.c. current;
- wherein
- the first port is isolated from the second port, and the third port is isolated from the fourth port in terms of direct current, respectively;
- said d.c. current path being provided with the following in a direction of said supplied d.c. current:
- a terminal for supplying the supplied d.c. current,
- a first circuit for making a d.c. connection of the terminal and the fourth port while isolated the fourth radio frequency signal,
- the first variable radio frequency resistive element which is coupled to the second port,
- a second circuit which makes a radio frequency connection of the first variable radio frequency resistive element and the ground while making d.c. isolation, and makes a d.c. connection of the first variable radio frequency resistive element and the first port while isolating the second radio frequency signal, and
- the second variable radio frequency resistive element which is coupled to the third port and a ground.
9 more elements
A variable attenuator comprising:
- a multiport coupler having a first port, a second port, a third port, and a fourth port, the second, third, and fourth ports being responsive to the first port so that when a first radio frequency signal is inputted in the first port, a second radio frequency signal being in-phase with the first radio frequency signal appears at the second port, a third radio frequency signal being in 90.degree.--delayed phase with the first radio frequency signal appears at the third port, and a fourth radio frequency signal appears at the fourth port, the fourth radio frequency signal having a first signal portion in 90.degree.--delayed phase with the second radio frequency signal and a second signal portion in opposite phase with the third radio frequency signal;
- a single d.c. current path through which a supplied d.c. current flows according to a required attenuation;
- and
- first and second variable radio frequency resistive elements which are disposed on said d.c. current path, that make up at least a part of a termination impedance of the second and third ports, respectively, and that produce resistance of a value corresponding to a value of the supplied d.c. current;
- wherein
- a signal input terminal for inputting an input radio frequency signal to be attenuated, which is coupled to the first port, and
- a signal output terminal for outputting an attenuated radio frequency signal, which is coupled to the fourth port.
4 more elements
A variable attenuator comprising:
- a multiport coupler having a first port, a second port, a third port, and a fourth port, the second, third, and fourth ports being responsive to the first port so that when a first radio frequency signal is inputted in the first port, a second radio frequency signal being in-phase with the first radio frequency signal appears at the second port, a third radio frequency signal being in 90.degree.--delayed phase with the first radio frequency signal appears at the third port, and a fourth radio frequency signal appears at the fourth port, the fourth radio frequency signal having a first signal portion in 90.degree.--delayed phase with the second radio frequency signal and a second signal portion in opposite phase with the third radio frequency signal;
- a single d.c. current path through which a supplied d,c. current flows according to a required attenuation;
- first and second variable radio frequency resistive elements which are disposed on said d.c. current path, that make up at least a part of a termination impedance of the second and third ports, respectively, and that produce resistance of a value corresponding to a value of the supplied d.c. current;
- a first termination circuit for terminating the second radio frequency signal appearing at the second port, and including the first variable radio frequency resistive element;
- and
- a second termination circuit for terminating the third radio frequency signal appearing at the third port, and including the second variable radio frequency resistive element.
3 more elements
A variable attenuator comprising:
- a multiport coupler having a first port, a second port, a third port, and a fourth port, the second, third, and fourth ports being responsive to the first port so that when a first radio frequency signal is inputted in the first port, a second radio frequency signal being in-phase with the first radio frequency signal appears at the second port, a third radio frequency signal being in 90.degree.--delayed phase with the first radio frequency signal appears at the third port, and a fourth radio frequency signal appears at the fourth port, the fourth radio frequency signal having a first signal portion in 90.degree.--delayed phase with the second radio frequency signal and a second signal portion in opposite phase with the third radio frequency signal;
- a single d.c. current path through which a supplied d.c. current flows according to a required attenuation;
- and
- first and second variable radio frequency resistive elements which are disposed on said d.c. current path, that make up at least a part of a termination impedance of the second and third ports, respectively, and that produce resistance of a value corresponding to a value of the supplied d.c. current, wherein said first and second variable radio frequency resistive elements are first and second PIN diodes, respectively.
1 more element
A variable attenuator comprising:
- a multiport coupler having a first port for receiving an input signal, a second port, a third port, and a fourth port for outputting an attenuated signal;
- a first variable radio frequency resistive element coupled to the second port of the multiport coupler;
- a second variable radio frequency resistive element coupled to the third port of the multiport coupler;
- and
- a plurality of interconnected circuit elements coupled to the ports of the multiport coupler, and the first and second variable radio frequency resistive elements, to form a d.c. current path that enables a d.c. current to flow through each of the ports of the multiport coupler and the first and second radio frequency resistive elements, the attenuated signal being determined according to the input signal and the d.c. current.
2 more elements
A variable attenuator comprising:
- coupling means for providing coupling between a first port that receives a signal to be attenuated, a second port, a third port, and a fourth port that outputs an attenuated signal;
- first resistance means for providing variable radio frequency resistance to the second port of the coupling means;
- second resistance means for providing variable radio frequency resistance to the third port of the coupling means, wherein the first, second, third, and fourth ports of the coupling means, and the first and second resistance means form a d.c. current path;
- and
- interconnecting means for interconnecting the ports of the multiport coupler, and the first and second resistance means, to form a d.c. current path that enables a d.c. current to flow through each of the ports of the coupling means and the first and second resistance means, the attenuated signal being determined according to the input signal and the d.c. current.
2 more elements
Dependencies are inferred from the claim text.