Transformer-Capacitor Power Combiner for Balanced CMOS RF

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Solution Overview

Problem

Wilkinson power combiners are unsuitable for CMOS RF circuits due to manufacturing limitations and are single-ended, making them incompatible with balanced signals, which are preferred in CMOS circuits for low voltage power supply applications.

Innovation Solution

Replacing a portion or the entirety of the transmission line in a Wilkinson power combiner with a circuit comprising capacitors and transformers, which provide a predetermined phase shift, allowing the device to function as both a power combiner and splitter, suitable for CMOS RF circuits by using capacitors to cancel leakage inductance and transformers to achieve phase shifting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a traditional Wilkinson power combiner with transmission lines is used, then signal combining and isolation are achieved, but the device is unsuitable for CMOS RF circuits due to manufacturing limitations and is single-ended making it incompatible with balanced signals

Engineering Contradiction:

Improvecompatibility with CMOS RF circuits and balanced signalsVSAvoidmanufacturing suitability

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent replaces the mechanical transmission line structure with an electrical circuit implementation using capacitors and transformers. This substitution allows the power combiner to be manufactured using standard CMOS processes while maintaining the required electrical functionality, including balanced signal compatibility and signal isolation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental operating parameters by using capacitors with specific capacitance values and transformers with specific turns ratios to achieve the same electrical characteristics (phase shift, impedance transformation, isolation) that were previously achieved through transmission line physical dimensions and geometry.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If transmission lines are used to achieve phase shift and signal transfer, then the Wilkinson combiner function is achieved, but the device complexity increases and manufacturing becomes difficult

Engineering Contradiction:

Improvesignal isolation and combining functionVSAvoidcircuit structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the transmission line function into discrete electrical components: capacitors for phase shift and impedance transformation, and transformers for signal coupling and isolation. This segmentation allows each component to be independently optimized and manufactured using standard CMOS processes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces capacitors and transformers as intermediary elements that mediate the signal transfer between input and output terminals, replacing the direct transmission line connection. These intermediaries provide the necessary electrical functionality while enabling CMOS compatibility and simplified manufacturing.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 the use of the device in CMOS RF circuits, supporting balanced signals and offering flexibility in impedance matching, suitable for low power supply voltages, and is more suitable for manufacturing processes than traditional Wilkinson power combiners.

Implementation Method 1

The first means comprises a first capacitance connected between a first pair of nodes, a second capacitance connected between a second pair of nodes

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

a first transformer having a first winding connected between the first pair of nodes and a second winding connected between the second pair of nodes

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS20140210542A1Power splitter and combiner

Publication Date: 2014.07.31 QUALCOMM TECH INT

AI summary

An electronic device is described, the device including a first circuit arranged to transfer a signal with a first predetermined phase shift, a second circuit, connected in series with the first circuit, arranged to transfer a signal with a second predetermined phase shift, and a resistance connected in parallel with the first and second circuits, wherein the first circuit includes a first capacitance connected between a first pair of nodes, a second capacitance connected between a second pair of nodes, and a first transformer having a first winding connected between the first pair of nodes and a second winding connected between the second pair of nodes.