Frequency-Adaptive Input Matching Circuit for Wideband Amplifiers
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Solution Overview
Problem
Current front-end drive amplifiers have a narrow frequency width, limiting their ability to support multiple communication frequency bands, resulting in high chip area overheads and matching deterioration at high frequencies.
Innovation Solution
An input matching circuit incorporating an inductive branch with adjustable inductance and a field-effect transistor, allowing the inductance value to vary with signal frequency to achieve LC parallel resonance, ensuring impedance matching across a wider frequency bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional front-end drive amplifier with fixed inductance is used, then the circuit structure is simple, but the frequency bandwidth supporting input matching is narrow
Solution Approach 1:
The patent implements dynamic inductance adjustment by introducing a controllable inductor (implemented through a switchable inductor bank) that can change its inductance value based on the operating frequency band. This allows the input matching circuit to adapt to different frequency ranges while maintaining a relatively compact structure, thus resolving the contradiction between bandwidth adaptability and circuit complexity.
Solution Approach 2:
The patent changes the inductance parameter dynamically by switching between different inductor values based on the detected frequency band. This parameter adjustment enables the amplifier to maintain optimal input matching across a wide frequency range (sub-6G bands) without requiring completely different circuit designs for each band, thereby improving adaptability while controlling complexity.
2Adaptability or versatility
If multiple front-end drive amplifiers are used to cover different frequency bands, then the frequency bandwidth is improved, but the chip area overhead increases
Solution Approach 1:
The patent designs a universal front-end drive amplifier that can operate across multiple frequency bands by incorporating an adjustable inductance network. This single amplifier circuit can be reconfigured to match different frequency bands through the controllable inductor, eliminating the need for multiple dedicated amplifiers for different bands and thus reducing chip area while maintaining broad frequency coverage.
Solution Approach 2:
By making the inductance value dynamically adjustable based on the operating band, the amplifier becomes a multi-functional component that can serve multiple frequency bands. This dynamic reconfiguration capability allows one amplifier to replace what would traditionally require several fixed-frequency amplifiers, significantly reducing the required chip area.
3Reliability
If the inductance value is fixed in the input matching circuit, then the circuit is simple to design, but matching deterioration occurs at high frequencies
Solution Approach 1:
The patent adjusts the inductance parameter as a function of frequency by implementing a switchable inductor network that selects appropriate inductance values for different frequency bands. This ensures that the input matching remains optimal across the entire sub-6G frequency range, preventing matching deterioration at high frequencies while keeping the adjustment mechanism relatively simple through systematic inductor switching.
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 front-end drive amplifier to support more communication frequency bands with reduced chip area overheads and maintains impedance matching at high frequencies, avoiding matching deterioration.
Implementation Method 1
the equivalent inductor L of the inductive branch between the signal input end and the ground and parasitic capacitance Cgs of the field-effect transistor can reach LC parallel resonance, to ensure that impedance of an LC parallel circuit at the frequency of the input signal is infinite
Data Source
Figure 1
Figure 2a~2b
Figure 3~4a
AI summary
An input matching circuit and a related apparatus are provided. The input matching circuit includes an inductive branch, a first resistor, and a field-effect transistor, the inductive branch includes one or more inductors and a second resistor, a first end of the first resistor is connected to a signal input end, and a second end of the first resistor is grounded. The signal input end is configured to provide a signal input for the input matching circuit, an input end of the inductive branch is connected to the signal input end, and an output end of the inductive branch is grounded. An inductance value of an equivalent inductor of the inductive branch between the signal input end and the ground varies with adjustment of a frequency of a signal input by the signal input end.