GaN Rotating-Coefficient FIR Filter for Co-Site Interference
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Solution Overview
Problem
Radar systems operating at high frequencies with high signal power face limitations in implementing FIR filters due to the expense and difficulty of analog-to-digital conversion and the limited operational ranges of semiconductor devices used in digital and analog implementations, respectively.
Innovation Solution
The implementation of a finite impulse response (FIR) filter using Gallium Nitride (GaN) components, which provides high linearity operation for high-powered signals, includes multiple parallel signal paths with sample-and-hold circuits and multipliers, and a controller to adjust delays and tap coefficients, optimizing power consumption and spurious performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If digital FIR filter implementation is used, then filter precision and flexibility are improved, but analog-to-digital conversion cost and complexity increase
Solution Approach 1:
The patent replaces the mechanical/electronic analog-to-digital conversion process with a direct analog implementation using GaN devices. The FIR filter operates entirely in the analog domain, substituting the need for ADCs and digital processing with analog multipliers, adders, and delay elements based on GaN technology, thereby maintaining filter precision while eliminating conversion complexity
Solution Approach 2:
The patent changes the operational parameters of semiconductor devices by using GaN material instead of traditional silicon-based devices. This parameter change enables the devices to operate at high frequencies and high power levels directly in analog mode, achieving digital-like filter flexibility and precision without requiring analog-to-digital conversion
2Device complexity
If analog FIR filter implementation is used, then device simplicity is improved, but operational frequency and power range are limited
Solution Approach 1:
The patent employs Gallium Nitride (GaN) composite material properties to build analog filter components that simultaneously achieve simplicity of analog structure with the extended operational capabilities typically associated with digital systems. GaN's high electron mobility and breakdown voltage enable the analog circuit to operate at high frequencies and power levels
3Power
If high signal power operation is implemented, then radar system performance is improved, but linearity and spurious performance deteriorate
Solution Approach 1:
The patent changes the material parameter from traditional semiconductors to GaN, which fundamentally alters the device characteristics to support high-power operation with maintained linearity. GaN devices exhibit superior breakdown voltage and electron saturation velocity, allowing them to handle high signal powers while maintaining faithful signal reproduction with minimal spurious emissions
Data Source
AI summary
A finite impulse response (FIR) filter including an input of the FIR filter that receives an RF input signal, a clock input configured to receive a clock signal, an output of the FIR filter that provides a filtered output signal, a plurality of signal paths including a plurality of sample-and-hold circuits and a plurality of multipliers arranged in parallel, each signal path including a respective sample-and-hold circuit and a respective multiplier being configured to receive the RF input signal and the clock signal to provide a modulated output signal, an adder configured to receive n modulated output signals from the plurality of signal paths and combine the n modulated output signals to produce the filtered output signal, and a controller.