Wideband vector modulator and phase shifter
An apparatus includes a first circuit and a plurality of second circuits. The first circuit may be configured to generate a pair of quadrature signals from a radio-frequency signal. The second circuits may each comprise a plurality of cascode amplifiers. The cascode amplifiers may be connected in parallel. The cascode amplifiers may be configured to generate a plurality of intermediate signals by modulating the quadrature signals in response to a first control signal and a second control signal. The first control signal generally switches a contribution of the cascode amplifiers in the generation of the intermediate signal. The second control signal may adjusts a total current passing through all of the cascode amplifiers.
1. An apparatus comprising:
a first circuit configured to generate a pair of quadrature signals from a radio-frequency signal; and
a plurality of second circuits each comprising a plurality of cascode amplifiers, wherein (i) said cascode amplifiers are connected in parallel, (ii) said cascode amplifiers are configured to generate a plurality of intermediate signals by modulating said quadrature signals in response to a first control signal and a second control signal, (iii) said first control signal switches a contribution of said cascode amplifiers to said intermediate signals, (iv) said second control signal adjusts a total current passing through all of said cascode amplifiers, and (v) said cascode amplifiers each comprise a plurality of transistors scaled relative to neighboring ones of said cascode amplifiers to make different contributions to said intermediate signals.
2. The apparatus according to claim 1 , wherein said modulation does not vary in response to process variations, voltage variations and temperature variations.
3. The apparatus according to claim 1 , wherein said first circuit comprises a wideband quadrature all-pass filter.
4. The apparatus according to claim 1 , further comprising a third circuit configured to generate an output signal by adding said intermediate signals, wherein said output signal has a programmable phase relative to said radio-frequency signal.
5. The apparatus according to claim 1 , wherein (i) each of said cascode amplifiers is coupled to a variable current source through a corresponding resistor and (ii) said corresponding resistors are scaled inversely to said transistors.
6. The apparatus according to claim 5 , wherein said second control signal adjusts a current of said variable current source.
7. The apparatus according to claim 1 , wherein (i) said first control signal comprises a plurality of components and (ii) each one of said components controls one of a plurality of transistors in a corresponding one of said cascode amplifiers.
8. The apparatus according to claim 1 , wherein said radio-frequency signal has a frequency of at least one of (i) a radio frequency, (ii) a millimeter-wave frequency, (iii) a microwave frequency or (iv) any combination thereof.
9. The apparatus according to claim 1 , wherein said radio-frequency signal has a frequency in a range of 24 gigahertz to 44 gigahertz.
10. The apparatus according to claim 1 , wherein said first circuit and said second circuit form part of a two-dimensional antenna network.
11. The apparatus according to claim 1 , wherein said first circuit and said second circuit form part of a fifth-generation wireless communications system.
12. A method for vector modulation and phase shifting, comprising steps of:
generating a pair of quadrature signals based on a radio-frequency signal; and
generating a plurality of intermediate signals using a plurality of circuits by modulating said quadrature signals in response to a first control signal and a second control signal, wherein (i) each of said circuits is configured as a plurality of cascode amplifiers, (ii) said cascode amplifiers are connected in parallel, (iii) said first control signal switches a contribution of said cascode amplifiers to said intermediate signals, (iv) said second control signal adjusts a total current passing through all of said cascode amplifiers, and (v) said cascode amplifiers each comprise a plurality of transistors scaled relative to neighboring ones of said cascode amplifiers to make different contributions to said intermediate signals.
13. The method according to claim 12 , further comprising the step of:
generating an output signal by adding said intermediate signals, wherein said output signal has a programmable phase relative to said radio-frequency signal.
14. The method according to claim 12 , wherein the steps are implemented in (i) a two-dimensional antenna network, (ii) a fifth-generation wireless communications system or (iii) any combination thereof.