Microwave Semiconductor Amplifier Output Matching Circuit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Microwave semiconductor amplifiers face challenges in achieving high power added efficiency at microwave frequencies due to impedance matching issues between semiconductor amplifying elements and external loads, particularly in maintaining inductive impedance for harmonics while minimizing insertion loss and ensuring wide bandwidth.
Innovation Solution
The implementation of an output matching circuit with a bonding wire and impedance converting circuits made of transmission lines, where the characteristic impedance and electrical length are carefully selected to match the fundamental impedance to the semiconductor amplifying element's output impedance and set the second harmonic impedance close to open-circuit impedance, thereby achieving high power added efficiency and wide bandwidth without increasing insertion loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a higher harmonic processing circuit using a stub is provided near the chip to set the second harmonic impedance near open-circuit impedance, then power added efficiency is increased, but insertion loss increases and bandwidth is narrowed
Solution Approach 1:
The patent moves the harmonic processing function from the near-chip area to a distant location connected via transmission line. By utilizing the transmission line's electrical length and characteristic impedance, the stub circuit can provide the required open-circuit impedance at the second harmonic frequency without being physically adjacent to the chip, thereby reducing insertion loss and bandwidth narrowing effects.
Solution Approach 2:
The transmission line acts as an intermediary between the stub circuit and the chip. It transforms the impedance characteristics and allows the stub to provide second harmonic open-circuit impedance without directly affecting the chip's output, thus minimizing insertion loss while maintaining the desired harmonic impedance.
2Use of energy by moving object
If a higher harmonic processing circuit using a stub is provided near the chip to set the second harmonic impedance near open-circuit impedance, then power added efficiency is increased, but bandwidth is narrowed
Solution Approach 1:
By relocating the stub circuit to a distant position connected via transmission line, the patent achieves second harmonic impedance control without constraining the bandwidth. The transmission line's electrical length is designed to provide the required impedance transformation at the center frequency while maintaining wider bandwidth operation compared to near-chip stub configurations.
3Reliability
If impedance matching circuit is cascaded via higher harmonic processing circuit, then second harmonic impedance is set near open-circuit impedance, but insertion loss increases
Solution Approach 1:
The patent combines the impedance matching function and the second harmonic open-circuit impedance setting function into a single integrated output matching circuit. This eliminates the need for cascaded circuits, reducing the number of components and minimizing insertion loss while achieving both impedance matching and harmonic control objectives.
Solution Approach 2:
The output matching circuit is designed to perform multiple functions simultaneously: it provides impedance matching at the fundamental frequency and creates open-circuit impedance at the second harmonic frequency. This multi-functional design eliminates the need for separate harmonic processing circuits, thereby reducing insertion loss.
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
This configuration allows for high power added efficiency and wide bandwidth operation by effectively matching the fundamental and second harmonic impedances, suppressing the second harmonic component, and maintaining a simple structure, making it suitable for radio communication devices and radar systems.
Implementation Method 1
an output matching circuit which has a first impedance converting circuit and a bonding wire connected in this order from the output electrode, and the second harmonic impedance seen from a second reference plane which is an output electrode of the semiconductor amplifying element toward a load is inductive
Data Source
Figure 1
Figure 2A~2B
Figure 3~4
AI summary
A microwave semiconductor amplifier includes a semiconductor amplifier element (14), an input matching circuit (12) and an output matching circuit (20). The semiconductor amplifying element (14) includes an input electrode and an output electrode and has a capacitive output impedance. The input matching circuit (12) is connected to the input electrode. The output matching circuit (20) includes a bonding wire (15) and a first transmission line (16). The bonding wire (15) includes first and second end portions. The first end portion is connected to the output electrode. The second end portion is connected to one end portion of the first transmission line (16). A fundamental impedance and a second harmonic impedance seen toward the external load change toward the one end portion. The second harmonic impedance at the one end portion has an inductive reactance. The output matching circuit (20) matches the capacitive output impedance of the semiconductor amplifying element (14) to the fundamental impedance of the external load.