UHF Balun Device Using Printed PCB Traces
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Solution Overview
Problem
Conventional RF baluns for UHF signals have limited frequency range and high fabrication costs due to the use of expensive magnetic cores and soldering processes, making them unsuitable for broader UHF band applications.
Innovation Solution
A balun device comprising a dielectric base plate with conductive connection pads, a printed conductive track, and a conductive ground pattern, which are directly formed on the base plate to match single-ended and differential signals, reducing fabrication costs and expanding the frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional RF balun uses a magnetic core with windings, then it achieves wide working frequency band, but it results in high fabrication cost due to expensive materials and soldering process
Solution Approach 1:
The patent extracts and eliminates the magnetic core component from the traditional RF balun structure. The balun function is achieved solely through PCB trace configurations (microstrip or coplanar waveguide structures), removing the need for expensive magnetic materials and complex winding processes while maintaining wide frequency band performance from 470 MHz to 770 MHz
Solution Approach 2:
The patent replaces the mechanical assembly of magnetic core and hand-wound coils with a planar PCB-based electromagnetic structure. The balun functionality is implemented through printed circuit board traces that create the necessary electromagnetic fields, eliminating manual soldering and mechanical assembly steps while reducing fabrication cost
2Ease of manufacture
If a conventional balun uses directly formed patterns on PCB, then it reduces fabrication cost, but it results in limited working frequency range
Solution Approach 1:
The patent applies different local quality characteristics to different regions of the PCB trace structure. Specific sections of the microstrip or coplanar waveguide are designed with varying impedance values, width ratios, and spacing to achieve proper differential-to-single-ended signal conversion across the UHF band. The ground pattern configuration also varies locally to optimize performance at different frequency points within 470-770 MHz
Solution Approach 2:
The patent utilizes parameter changes in the PCB trace geometry to achieve wide frequency coverage. By adjusting trace width, spacing, length ratios, and impedance values in different sections of the balun structure, the design accommodates the entire UHF television band from 470 MHz to 770 MHz, transforming the limited frequency response into a broad operating range while maintaining direct PCB fabrication
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 balun device supports RF signals within the UHF band from 470 MHz to 770 MHz with an improved bandwidth of about 300 MHz, suitable for digital television frequencies, while maintaining low fabrication costs by eliminating the need for magnetic cores and soldering processes.
Implementation Method 1
The printed conductive track is formed on the dielectric base plate and interconnects electrically the conductive connection pads. The conductive ground pattern is formed on the dielectric base plate, and is surrounded by and spaced apart from the printed conductive track and the conductive connection pads.
Data Source
AI summary
A balun device for UHF signals includes two conductive connection pads, a printed conductive track and a conductive ground pattern that are formed on a dielectric base plate. The conductive connection pads are connectable respectively with a pair of first signal lines for a pair of differential signals. One of the conductive connection pads is further connectable with a second signal line for a single-ended signal. The printed conductive track interconnects electrically the conductive connection pads. The conductive ground pattern is surrounded by and spaced apart from the printed conductive track and the conductive connection pads.