Active All-Pass Phase Shifter for Wideband Low-Noise Beam Control
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Solution Overview
Problem
Existing phase-shifting techniques in modem RADAR and wireless communications suffer from signal loss and limited bandwidth due to passive methods, making precise beam control difficult as desired bandwidths and frequencies increase.
Innovation Solution
A low-noise wideband active phase shifter using transconductance cells, fixed and tunable LC series networks, and all-pass lattice networks to achieve precise phase control with reduced noise and wideband frequency response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional passive phase-shifting methods (switched-line, switched termination, switched loading, filtering) are used, then phase control is achieved, but signal loss increases and bandwidth is limited
Solution Approach 1:
The patent replaces traditional passive mechanical/electrical switching mechanisms with an active all-pass lattice network using transconductance cells and variable capacitors. This substitution eliminates the inherent signal losses of switched-line and switched-termination methods while achieving continuous phase control across wide bandwidths through electronic tuning of the lattice network parameters.
Solution Approach 2:
The invention achieves wideband operation by dynamically changing the parameters of the all-pass lattice network through variable capacitors controlled by binary-coded inputs. The phase shift is controlled by adjusting capacitance values in the lattice network, allowing continuous phase adjustment from 0 to 360 degrees across a wide frequency range without the bandwidth limitations of traditional filtering methods.
2Adaptability or versatility
If traditional passive phase-shifting methods are used, then phase control is achieved, but bandwidth is limited
Solution Approach 1:
The patent replaces traditional passive mechanical/electrical switching mechanisms with an active all-pass lattice network using transconductance cells and variable capacitors. This substitution eliminates the inherent signal losses of switched-line and switched-termination methods while achieving continuous phase control across wide bandwidths through electronic tuning of the lattice network parameters.
Solution Approach 2:
The invention achieves wideband operation by dynamically changing the parameters of the all-pass lattice network through variable capacitors controlled by binary-coded inputs. The phase shift is controlled by adjusting capacitance values in the lattice network, allowing continuous phase adjustment from 0 to 360 degrees across a wide frequency range without the bandwidth limitations of traditional filtering methods.
3Loss of energy
If active phase-shifting methods are used to reduce loss, then signal loss is reduced, but noise may increase
Solution Approach 1:
The patent introduces an all-pass lattice network as an intermediary structure that provides phase control without the noise-generating mechanisms of traditional active phase shifters. The lattice network, composed of transconductance cells and variable capacitors, achieves phase shifting through reactive energy storage and exchange rather than amplification or switching, thereby minimizing noise while maintaining low signal loss.
4Measurement precision
If high-frequency operation is required, then beam direction control precision becomes increasingly difficult, but wideband operation is needed
Solution Approach 1:
The patent employs binary-coded feedback control where four binary inputs (A, B, C, D) selectively activate variable capacitors in the all-pass lattice network. This feedback mechanism allows precise digital control of the phase shift amount, enabling accurate beam direction control at high frequencies while maintaining wideband operation through programmable capacitance combinations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The phase shifter provides precise 360-degree phase control with 4-degree resolution across a wide frequency range, minimizing noise and signal loss, enabling efficient beam steering in high-frequency applications.
Implementation Method 1
These phase relations (e.g., signals of a common frequency but having different delay relations with respect to one another) are generated by shifting the phase of these electronic signal by different angular amounts
Implementation Method 2
The fixed LC series network and the tunable LC series network form an all-pass lattice network with the first and second transconductance cells
Implementation Method 3
Each of the first and second transconductance cells include a transistor, a feedback network, and input and output biasing networks
Implementation Method 4
The feedback network electrically couples the input and output terminals of the transistor
Implementation Method 5
a fixed LC series network and a tunable LC series network
Implementation Method 6
a fixed LC series network and a tunable LC series network
Data Source
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AI summary
Apparatus and associated methods relate to a low-noise wideband active phase shifter. The low-noise wideband active phase shifter includes first and second transconductance cells (14,16), a fixed LC series network (18L1,18L2,18C) and a tunable LC series network (18Ll,16TL,20C1...4,20T1...4) configured to form an all-pass lattice network. The first and second transconductance cells, each include a transistor (14T,16T), a feedback network (14FB,14RFB,14CFB,16FB,16RFB,16CFB), and a transistor biasing network (14NBIAS-14RBIAS-14CBIAS-16BIAS-16RBIAS-16CBIAS)- The transistor has an input terminal and an output terminal. The negative feedback network electrically couples the input and output terminals of the transistor. The biasing network provides input and output biasing of the transistor. The fixed LC series network connects between the first and the second transconductance cells. The tunable LC series network connects between the first and the second transconductance cells.