Doherty RF Module Layout for Compact Impedance Conversion
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Solution Overview
Problem
The size of radio-frequency modules incorporating Doherty amplifiers increases due to the expansion of impedance conversion circuits.
Innovation Solution
A compact radio-frequency module design incorporating a Doherty amplifier, featuring a module substrate with first and second amplifiers, a transformer with input and output coils, and capacitive elements integrated into a semiconductor IC, along with transmission lines and capacitors, to reduce module size and suppress harmonics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If an impedance conversion circuit is added to the Doherty amplifier, then the amplifier can achieve efficient operation in both low and high output regions, but the module size increases
Solution Approach 1:
The patent combines the impedance conversion circuit with the semiconductor IC chip that contains the first and second amplifiers. The impedance conversion circuit is integrated onto the same substrate as the amplifiers, merging multiple functional components into a single compact unit. This integration eliminates the need for separate discrete impedance conversion circuits, thereby reducing overall module size while maintaining the efficiency benefits of impedance conversion across different output regions.
Solution Approach 2:
The patent utilizes three-dimensional packaging and vertical stacking techniques to arrange the amplifiers and impedance conversion circuit in multiple layers on the semiconductor IC. By transitioning from a planar two-dimensional layout to a three-dimensional structure, the circuit components are compacted vertically, reducing the horizontal footprint and overall module area while preserving all necessary circuit functions.
2Area of stationary object
If the impedance conversion circuit size is reduced to shrink module size, then the module becomes more compact, but transmission loss increases and electromagnetic coupling is enhanced
Solution Approach 1:
The patent employs different transmission line geometries and impedance values in different regions of the circuit. The transmission lines are designed with locally optimized characteristics - wider traces where current is high to reduce resistive loss, and properly controlled impedance sections to minimize reflections. This local optimization allows compact routing without sacrificing transmission efficiency, reducing energy loss even in the reduced-size module.
3Area of stationary object
If the impedance conversion circuit size is reduced to shrink module size, then the module becomes more compact, but electromagnetic coupling between components increases
Solution Approach 1:
The patent introduces ground planes and shielding structures as intermediary elements between the amplifiers and impedance conversion circuit. These ground planes act as electromagnetic shields, blocking unwanted coupling between adjacent circuit elements. The intermediary ground layers provide electromagnetic isolation while maintaining the compact three-dimensional layout, allowing close proximity of components without harmful interference.
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 design achieves a compact radio-frequency module with efficient amplification and reduced size, enabling high efficiency in both low and high output regions while minimizing transmission loss and electromagnetic coupling.
Implementation Method 1
a transformer (20) including an input-side coil (201) and an output-side coil (202)
Implementation Method 2
a first capacitive element (33). One end of the first capacitive element (33) is connected to the other end of the first transmission line (31) and the one end of the second transmission line (32) and the other end of the first capacitive element (33) is grounded
Data Source
AI summary
A radio-frequency module includes a module substrate, a carrier amplifier and a peak amplifier, a transformer, and a phase adjustment circuit. The carrier amplifier and the peak amplifier are included in a semiconductor IC. One end of an input-side coil is connected to an output terminal of the carrier amplifier. One end of the output-side coil is connected to a signal output terminal.