Capacitive Phase Shifter for High-Speed Wideband Signal Processing
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Solution Overview
Problem
Existing phase shifters using discrete-time analog circuits face challenges in achieving high-speed operation to handle wideband signals due to the large number of switches required for converting continuous-time analog signals to discrete-time signals.
Innovation Solution
A phase shifter design that includes a first and second capacitor connected to input signals with a phase difference, and a combining circuit that outputs a combined signal based on the capacitance ratio between the capacitors, allowing for high-speed operation without switches in the signal path, enabling efficient handling of wideband signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a discrete-time analog circuit with switches is used to convert continuous-time analog signals to discrete-time signals, then phase control is achieved, but the operation speed is reduced and wideband signal handling becomes difficult
Solution Approach 1:
The patent removes switches from the signal path by extracting the discrete-time conversion function and replacing it with a continuous-time capacitive network. The switch-based discrete-time analog circuit is replaced with capacitors connected to I and Q input signals, eliminating the speed limitation imposed by switch operation while maintaining phase control capability through capacitance ratio adjustment.
Solution Approach 2:
The patent substitutes the mechanical/electronic switching mechanism with an electrostatic capacitive division mechanism. Instead of using switches to sample and hold signals in discrete time, the invention uses capacitors to continuously divide the signal based on capacitance ratios, replacing the discrete-time switching system with a continuous-time passive analog system that operates without mechanical or electronic switches.
2Adaptability or versatility
If a large number of switches are provided in the signal path for continuous-time to discrete-time conversion, then phase adjustment is enabled, but device complexity increases
Solution Approach 1:
The patent extracts and removes the complex switch-based discrete-time conversion circuitry from the signal path. By replacing the entire switch network with a simple capacitive division network, the invention eliminates the need for multiple switches, clock signals, and control logic while retaining phase adjustment capability through continuous capacitance ratio control.
Solution Approach 2:
The patent changes the fundamental operating parameter from discrete-time switching to continuous-time capacitance ratio control. By adjusting the capacitance values of the capacitors in the network, the phase can be continuously adjusted without requiring complex digital control logic or multiple discrete switching elements, thereby simplifying the overall device complexity.
3Measurement precision
If switch-based discrete-time conversion is used, then phase control is achieved, but power consumption increases
Solution Approach 1:
The patent substitutes the active switch-based discrete-time conversion system with a passive continuous-time capacitive network. The capacitors continuously divide the signal based on their capacitance ratios without requiring active switching operations, thereby eliminating the dynamic power consumption associated with charging and discharging switch nodes while maintaining phase control precision.
Solution Approach 2:
The capacitive network operates autonomously using the input signal itself to establish the voltage division ratio. The capacitors automatically adjust the signal distribution based on their capacitance values without requiring external control signals or active power management, allowing the circuit to self-regulate its operation and minimize power consumption.
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 solution enables high-speed operation and precise phase control for wideband signals, reducing the need for calibration and minimizing power consumption in wireless communication apparatuses, while maintaining stability across process variations and temperature changes.
Implementation Method 1
a first capacitor connected to a first line to which a first input signal is input, a second capacitor connected to a second line to which a second input signal having a first phase difference with respect to the first input signal is input
Data Source
AI summary
A phase shifter includes a first capacitor connected to a first line to which a first input signal is input, a second capacitor connected to a second line to which a second input signal having a first phase difference with respect to the first input signal is input, and a combining circuit that is connected to the first line and the second line and that outputs a combined signal having a phase determined depending on a first capacitance ratio between the first capacitor and the second capacitor.