Frequency tunable bi-directional active phased-array processing
A novel frequency tunable bi-directional phased array processing consisting of variable phase shifting and amplitude adjustment which employs a vector modulator and active combiner and splitter is proposed. Advantages of the proposed bi-directional a phased array processing includes the following 1) compact size; 2) high efficiency; 3) reduced passive trace loss and power consumption; 4) active current combining; 5) high input-output isolation; 6) high resolution and precise gain control and unequal combining or splitting; 7) phase-invariant amplifier design; 8) high accuracy and high-resolution phase shifter; 9) frequency tunability, within a small frequency range and/or a large frequency range; and 10) optimal unequal combining or splitting.
1. A frequency tunable bi-directional (BD) vector modulator, comprising: a frequency tunable quadrature phase coupler coupled to a first input-output (IO) terminal and two first matching networks (MN1s), wherein the quadrature phase coupler converts an input signal to an in-phase (I) signal and a quadrature-phase (Q) signal; a first network of parallel bi-directional variable gain transistor cores (BD-VGTCs) that receives the I signal, wherein the first network of BD-VGTCs amplifies the I signal by a first gain value and outputs an amplified in-phase (I′) signal onto a common node; a second network of parallel BD-VGTCs that receives the Q signal, wherein the second network of BD-VGTCs amplifies the Q signal by a second gain value and outputs an amplified quadrature-phase (Q′) signal onto the common node; and a shared second matching network (MN2) coupled to the common node and a second IO terminal for outputting an output signal, wherein the first network and the second network of BD-VGTCs share the same MN2, and wherein the BD vector modulator has an adjustable input impedance and an adjustable output impedance that match to the BD-VGTCs for both switched amplifier directions.
2. The frequency tunable bi-directional vector modulator of claim 1 , wherein the quadrature phase coupler employs a plurality of switch impedance circuits for achieving frequency tuning and maintaining amplitude balance and phase quadrature.
3. The frequency tunable bi-directional vector modulator of claim 1 , wherein the networks of parallel BD-VGTCs are combined at the common node with the frequency tunable shared second matching network (MN2).
4. The frequency tunable bi-directional vector modulator of claim 1 , wherein the networks of parallel BD-VGTCs share a common cascode transistor between the BD-VGTCs or between the I and Q Paths.
5. The frequency tunable bi-directional vector modulator of claim 1 , wherein the networks of parallel BD-VGTCs achieve extra resolution with reversal BD-VGTCs configured in one of reverse, non-reverse, both-on, or both-off states.
6. The frequency tunable bi-directional vector modulator of claim 1 , wherein each BDVGTC comprises one or more complementary differential transistor pairs for providing the different phase shift and amplitude adjustment settings.
7. The frequency tunable bi-directional vector modulator of claim 6 , wherein the networks of parallel BD-VGTCs achieve extra resolution with adjustable current biasing to control the transistor pairs.
8. The frequency tunable bi-directional vector modulator of claim 1 , wherein a number of BDVGTCs used for realizing phase shift values is significantly reduced using a linear combination of a number of basis transistor sizes in the BD-VGTCs.
9. The frequency tunable bi-directional vector modulator of claim 1 , wherein a resolution of the vector modulator is increased via a bias current adjustment.
10. The frequency tunable bi-directional vector modulator of claim 1 , wherein a signal polarity inversion in the I or Q path is achieved via a switch current direction or a differential polarity switch.