On-Die Directional Coupler Integration in RF Power Amplifiers
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Solution Overview
Problem
Existing wireless communication devices require separate RF power amplifiers and directional couplers, which increase size and cost due to the need for external couplers to monitor transmit output power.
Innovation Solution
Integration of a power amplifier core with multiple gain stages and an on-die directional coupler on a single semiconductor die, using bond wires for interconnection to split and monitor the transmit output power signal, thereby eliminating the need for a separate coupler.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If separate RF power amplifiers and directional couplers are used, then device functionality is ensured, but device size and cost increase
Solution Approach 1:
The patent combines the RF power amplifier and directional coupler into a single integrated device. The power amplifier includes an output network with transmission lines that are directly coupled to form the directional coupler structure, eliminating the need for separate external coupler components. This integration reduces device size and complexity while maintaining the functionality of both power amplification and power monitoring.
2Device complexity
If external directional couplers are used to monitor transmit output power, then power monitoring is achieved, but device cost increases
Solution Approach 1:
The directional coupler is integrated within the power amplifier device, with coupling ports directly accessible on the same substrate. The transmission lines in the output network are configured to provide both power amplification and power coupling functionality, eliminating the need for separate external coupler components and reducing overall device cost.
Solution Approach 2:
The output network transmission lines serve dual purposes: they function as the main power amplification path and simultaneously act as the directional coupler structure for power monitoring. This multi-functionality reduces the total component count and device cost while maintaining accurate power monitoring capability.
3Device complexity
If separate components are used for power amplifier and directional coupler, then component performance is optimized, but integration density decreases
Solution Approach 1:
The power amplifier and directional coupler are merged into a single integrated structure on the same substrate. The output network uses shared transmission lines that serve both amplification and coupling functions, achieving high integration density while maintaining the performance characteristics of both functions through proper electromagnetic design.
Data Source
AI summary
A power amplifier includes a power amplifier core including a plurality of gain stages to receive a radio frequency (RF) signal and to output an amplified RF signal, an output network coupled to the power amplifier core to receive the amplified RF signal and output a transmit output power signal, and a directional coupler coupled to the output network to obtain a coupled signal proportional to the transmit output power signal. Each of these components can be configured on a single semiconductor die, in an embodiment.