Resistive Power Detector Using Squared Terminal Voltages

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing power detectors in wireless transmitters face challenges in accurately measuring power delivered to antennas due to phase offsets between voltage and current sensors, especially at millimeter wave frequencies, and require bulky current sensing coils that are sensitive to impedance terminations, leading to inaccuracies.

Innovation Solution

The use of a resistive element coupled between the power amplifier and antenna, where both terminal voltages are squared and their difference is computed to measure power, eliminating the need for phase shifters and current sensing coils, and incorporating squaring circuits, low-pass filters, and multiplexers for accurate power measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If phase shifters and current sensing coils are used for power measurement, then power measurement capability is achieved, but measurement precision deteriorates due to phase offsets and impedance sensitivity

Engineering Contradiction:

Improvepower measurement precisionVSAvoidcomplexity of power detection circuit

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the problematic phase shifter and current sensing coil components from the power detection system. By using a resistive element with voltage sensing only, it removes the sources of phase offset errors and impedance sensitivity, thereby improving measurement precision while reducing device complexity

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the traditional mechanical/electromagnetic sensing approach (current sensing coils) with an electrical voltage sensing method across a resistive element. This substitution eliminates the need for phase alignment and complex electromagnetic sensing, simplifying the system while improving accuracy

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If current sensing coils are used for power measurement, then power measurement is enabled, but reliability worsens due to sensitivity to impedance terminations

Engineering Contradiction:

Improvestability of power measurementVSAvoidsensitivity to impedance terminations

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the potentially harmful effect of impedance variations into a benefit by using a resistive element where the voltage measurement is directly proportional to power. The resistive element's simplicity makes it inherently less sensitive to impedance termination issues compared to current sensing coils, improving reliability

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The resistive element acts as an intermediary between the power amplifier and antenna, providing a stable voltage measurement point that is not affected by impedance variations in the antenna or transmission line. This intermediary approach isolates the measurement from harmful impedance effects

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

This approach provides accurate measurement of power delivered to antennas without phase offset corrections and bulky coils, enhancing measurement precision and reducing errors, particularly at millimeter wave frequencies.

Implementation Method 1

both terminal voltages are squared and their difference is computed to measure power

Methodology Applied

Scientific EffectSquaring operation:

Implementation Method 2

incorporating squaring circuits, low-pass filters, and multiplexers for accurate power measurement

Methodology Applied

Scientific EffectLow-pass filtering: Filter (electronic)

Data Source

PatentUS11656254B2Power detector including squaring circuits

Publication Date: 2023.05.23 QUALCOMM INC

AI summary

In certain aspects, a method is provided for measuring power using a resistive element coupled between a power amplifier and an antenna. The method includes squaring a voltage from a first terminal of the resistive element to obtain a first signal, squaring a voltage from a second terminal of the resistive element to obtain a second signal, and generating a measurement signal based on a difference between the first signal and the second signal. In some implementations, the resistive element is implemented with a power switch.