Balanced UWB Directional Coupler for Compact GPR Signal Separation
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Solution Overview
Problem
Existing GPR scanners face challenges in reducing size and improving performance due to the physical dimensions of separate TX and RX antennas, and standard directional couplers are not optimized for GPR antennas with specific impedances, leading to higher internal reflections and reduced dynamic range.
Innovation Solution
A balanced ultra-wide band (UWB) directional coupler is designed for mono-static GPR scanners, featuring a compact structure with balanced interfaces and reduced internal reflections, optimized for 100-Ohm impedance, and incorporating waveguide structures on a thin PCB to minimize noise and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate TX and RX antennas are used in a bi-static design, then the antennas can operate with proper physical dimensions for GPR performance, but the overall size of the GPR scanner increases
Solution Approach 1:
The patent combines separate TX and RX antennas into a single integrated antenna structure that operates in mono-static mode, allowing the antenna to both transmit and receive radar signals while maintaining proper physical dimensions for GPR performance, thereby reducing overall scanner size without sacrificing performance
2Volume of moving object
If a single antenna is used for both TX and RX in a mono-static design, then the scanner size is reduced, but internal reflections from antenna interfaces increase and performance deteriorates
Solution Approach 1:
The patent introduces a directional coupler as an intermediary component between the single antenna and the signal processing circuitry. This directional coupler effectively separates transmitted and received signals, reducing internal reflections from antenna interfaces and improving GPR performance while maintaining the compact mono-static design
3Ease of manufacture
If standard 50-Ohm impedance directional couplers are used with GPR antennas, then standard interfaces are available, but internal reflections increase and dynamic range is reduced due to impedance mismatch
Solution Approach 1:
The patent changes the impedance parameter of the directional coupler from the standard 50-Ohm to 100-Ohm to match the characteristic impedance of GPR antennas. This impedance transformation reduces reflections at the interface between the directional coupler and the antenna, thereby improving the dynamic range and overall performance of the GPR system
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 a compact, high-performance GPR scanner with improved signal integrity and reduced susceptibility to external interference, facilitating superior compactness and performance over existing implementations.
Implementation Method 1
a first waveguide structure and a second waveguide structure separated from the first waveguide structure by a printed circuit board (PCB)
Implementation Method 2
both conductors have equal impedances along their lengths and equal impedances to an electrical potential (e.g. the ground). The two conductors are thus configured to carry signals with opposing amplitudes
Implementation Method 3
a first waveguide structure and a second waveguide structure separated from the first waveguide structure by a printed circuit board (PCB)
Data Source
AI summary
A ground-penetrating radar (GPR) scanner for investigating a sub-surface, wherein the GPR scanner comprises an antenna assembly configured for transmitting and receiving ultra-wide band (UWB) signals. The GPR scanner further comprises a directional coupler, a UWB signal generator configured for providing outgoing UWB signals through the directional coupler to the antenna assembly, a UWB signal sampling unit configured for receiving incoming UWB signals from the antenna assembly through the directional coupler, and an impedance. The directional coupler is configured as a balanced UWB directional coupler. It comprises a first port configured for receiving positive outgoing UWB signals from the UWB signal generator and a second port configured for receiving negative outgoing UWB signals from the UWB signal generator, wherein the second port is balanced with the first port.