Three-Winding Balun for Wideband Impedance Matching
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Solution Overview
Problem
The existing semiconductor device configurations, such as those described in Japanese Unexamined Patent Application Publication No. 2016-158053, face challenges in impedance matching between the differential power amplifier and subsequent circuits due to significant changes in load impedance with respect to frequency, resulting in a narrow frequency band for successful impedance matching.
Innovation Solution
A balun configuration is introduced, comprising first, second, and third windings with specific connections and electromagnetic couplings, along with capacitors, to achieve impedance matching across a wide frequency band by optimizing the parameters of the circuit elements, particularly in the power amplifier circuit, allowing for successful impedance matching between anterior and posterior circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional transmission matching circuit (balun) is used for impedance conversion and balanced-to-unbalanced conversion, then the circuit can perform the required signal conversion functions, but the load impedance changes significantly with frequency, resulting in a narrow frequency band for successful impedance matching
Solution Approach 1:
The balun is divided into multiple windings (first, second, and third windings) with specific turn ratios, allowing independent optimization of impedance transformation at different frequency points. This segmentation enables the circuit to maintain stable impedance matching across a wider frequency range by distributing the matching function across multiple winding segments.
Solution Approach 2:
The patent optimizes specific parameters including the number of turns of each winding (first, second, and third windings), the capacitance values of connected capacitors, and the physical dimensions of the windings. By carefully adjusting these parameters, the balun achieves stable impedance matching across an extended frequency band, transforming the narrowband conventional design into a wideband solution.
2Adaptability or versatility
If the number of windings and capacitors is increased to widen the frequency band, then impedance matching improves across a wider frequency range, but the device complexity increases
Solution Approach 1:
The balun combines multiple functions (impedance transformation, balanced-to-unbalanced conversion, and frequency band widening) into a single integrated structure with three windings and two capacitors. This merging approach achieves wideband impedance matching without requiring separate circuits for each function, thereby limiting the increase in overall device complexity.
Solution Approach 2:
The first, second, and third windings collectively perform multiple functions: impedance transformation, balanced-to-unbalanced conversion, and broadband matching. The capacitors connected to specific windings provide additional tuning capability. This multi-functionality allows the circuit to achieve wide frequency band coverage without proportionally increasing complexity.
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 proposed balun configuration effectively matches impedances across a wide frequency band, from 1.7 GHz to 2.7 GHz, compared to the narrow frequency range of 1.7 GHz to 2.45 GHz in previous designs, while maintaining stable power loss and return loss, thus enhancing the performance of the semiconductor device.
Implementation Method 1
third wiring that has a first end connected to the second end of the second wiring and a second end connected to an unbalanced line, to which an unbalanced signal is transmitted, and is electromagnetically coupled to the second wiring
Implementation Method 2
The first wiring is electromagnetically coupled to at least one of the second wiring and the third wiring
Implementation Method 3
a first capacitor that has a first end connected to the first end of the third wiring and a grounded second end; and a second capacitor that has a first end connected to the second end of the third wiring and a grounded second end
Data Source
AI summary
A balun includes: first wiring that has a first end connected to a first balanced line and a second end connected to a second balanced line; second wiring that has a grounded first end and a second end; third wiring that has a first end connected to the second end of the second wiring and a second end connected to an unbalanced line and is electromagnetically coupled to the second wiring; a first capacitor that has a first end connected to the first end of the third wiring and a grounded second end; and a second capacitor that has a first end connected to the second end of the third wiring and a grounded second end. The first wiring is electromagnetically coupled to at least one of the second wiring and the third wiring.