High-Frequency Output Circuit With LC Matching for Wideband Gain
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Solution Overview
Problem
High-frequency amplifiers in GHz bands face challenges with output matching, leading to unwanted reflections and abnormal oscillations, particularly in ultra-wide band communication systems, due to increased circuit area and power consumption.
Innovation Solution
A high-frequency circuit design incorporating a transistor with a fixed source terminal and a series circuit of inductor and capacitor between the drain terminal and the load, forming a band-pass filter to achieve wide-band output matching without increasing circuit area or power consumption, using a differential amplifier circuit and preamplifier stages with specific configurations of inductors, capacitors, and resistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If feedback amplifier or distributed amplifier is used to achieve wide-band output matching, then output matching is improved over wide band, but circuit area and power consumption increase
Solution Approach 1:
The patent changes the circuit configuration parameters by introducing a series LC circuit at the output node, transforming the output impedance characteristics to achieve wide-band matching without requiring complex feedback or distributed amplifier structures. This parameter change enables wide-band output matching while maintaining compact circuit area.
Solution Approach 2:
The series LC circuit acts as an intermediary element between the amplifier output and the load, providing impedance transformation and matching functionality. This intermediary structure enables wide-band output matching without requiring the entire amplifier circuit to be complex, thus reducing overall circuit area while maintaining reliability.
2Reliability
If feedback amplifier or distributed amplifier is used to achieve wide-band output matching, then output matching is improved over wide band, but power consumption increases
Solution Approach 1:
The patent modifies the output stage parameters by adding a series LC circuit, which provides impedance matching through reactive elements rather than requiring additional active amplifying devices. This approach achieves wide-band output matching while avoiding the increased power consumption associated with feedback or distributed amplifier configurations.
Solution Approach 2:
The series LC circuit serves as an intermediary matching network that provides wide-band output matching without requiring additional power-consuming active components. The reactive elements in the LC circuit provide impedance transformation passively, thus improving output matching reliability without increasing power consumption.
3Area of stationary object
If simple amplifier configuration is used, then circuit area and power consumption are reduced, but output matching deteriorates causing reflections and oscillations
Solution Approach 1:
The patent applies parameter changes by introducing a series LC circuit with specific inductance and capacitance values at the output node. This modification transforms the output impedance to achieve wide-band matching, preventing reflections and oscillations while maintaining a compact circuit configuration that does not significantly increase circuit area.
Solution Approach 2:
The series LC circuit acts as an intermediary matching network between the simple amplifier configuration and the load. This intermediary structure provides the necessary impedance transformation to achieve good output matching and prevent reflections and oscillations, while adding minimal circuit area compared to complex amplifier designs.
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 excellent output matching and flat gain over a wide band, minimizing circuit area and power consumption, while maintaining desired band-pass characteristics, thus preventing unwanted reflections and oscillations.
Implementation Method 1
a series circuit, including an inductor and a capacitor connected in series, provided between a connection point of the drain terminal of the transistor and the load and an output terminal of the high-frequency circuit, wherein a band-pass filter having a predetermined characteristic is configured by an output equivalent circuit expressing an output impedance of the transistor, the load, and the series circuit
Data Source
AI summary
The potential of a source terminal of a transistor is fixed; a load is connected to a drain terminal of the transistor; and an input signal is received by a gate terminal of the transistor. A series circuit including an inductor and a capacitor connected in series is provided between a connection point of the drain terminal of the transistor and the load and an output terminal of a high-frequency circuit. A band-pass filter having a prescribed characteristic is configured by an output equivalent circuit expressing an output impedance of the transistor, the load, and the series circuit.