Differential Power Amplifier Matching for Balanced Input Impedance
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Solution Overview
Problem
Existing radio frequency power amplifiers with differential structures face challenges in maximizing output power due to non-ideal effects at the grounded terminal of the matching network, leading to inconsistent impedances at the input ports of the matching network.
Innovation Solution
Incorporating a matching capacitor connected in series to the matching network, which enables the impedance difference between the two input ports of the matching network to be within a preset range, thereby ensuring consistent impedances and improving power output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a matching network with a grounded terminal is used to match the differential power amplifier to the single-ended antenna, then impedance matching is achieved, but non-ideal effects at the grounded terminal cause inconsistent impedances at the input ports, reducing power output
Solution Approach 1:
A virtual ground node is introduced as an intermediary between the two input ports of the matching network. This virtual ground node, created through capacitive coupling, mediates the impedance interaction between the ports and eliminates the non-ideal effects at the physical ground terminal, achieving consistent impedances at both input ports without requiring a direct ground connection.
Solution Approach 2:
The physical ground connection at the matching network terminal is extracted or removed from the signal path. By eliminating the direct ground connection that causes non-ideal effects, the patent avoids the impedance inconsistency problem while maintaining the necessary reference potential through the virtual ground created by capacitive coupling.
2Power
If the matching network is directly connected without additional components, then the circuit is simple, but the non-ideal effect at the grounded terminal prevents maximum power transfer
Solution Approach 1:
Capacitors are introduced as intermediary components to create a virtual ground node. These capacitors couple the two input ports without requiring a direct ground connection, thereby improving power transfer efficiency by eliminating the non-ideal ground effects while adding minimal circuit complexity.
Solution Approach 2:
The patent changes the impedance parameters at the input ports by introducing capacitive elements. This parameter change transforms the impedance characteristics to achieve consistency between the two ports, maximizing power transfer while maintaining a relatively simple circuit structure.
Data Source
AI summary
Disclosed is a power amplifier and a wireless transmitter. The power amplifier includes a power device and a matching network, where an output end of the power device is connected to an input end of the matching network, and the input end of the matching network includes two input ports. The power amplifier further includes a matching capacitor. The matching capacitor is connected in series to the matching network, to enable an impedance difference between the two input ports of the matching network to be within a preset range. The impedance difference between the two input ports of the matching network is enabled to be within the preset range. In this way, consistent impedances can be obtained at the two input ports of the input end of the matching network, thereby maximizing an output power of the power amplifier, and implementing true matching between the power amplifier and an antenna.