Time Gated RF Transmission Measurement for Inaccessible Ports

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Solution Overview

Problem

Conventional methods for determining the transmission response of a radio frequency (RF) device under test (DUT) are hindered when one or both ports of the DUT are not readily accessible, such as in cases where the DUT is installed in a structure like a cellular telephone tower or aircraft wing, making simultaneous connection to both ends impossible.

Innovation Solution

A method involving measuring the reflection response from one port of the DUT with a known reflective termination on the other port, followed by time gating to isolate the reflection data associated with the termination, thereby producing the transmission response of the DUT, which allows for determination without simultaneous access to both ports.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional VNA measurement methods are used to measure transmission response, then measurement precision is improved, but device complexity and accessibility requirements worsen

Engineering Contradiction:

Improvetransmission response measurement accuracyVSAvoidmeasurement system configuration complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

A known reflective termination is introduced as an intermediary element at the second port of the DUT. This termination reflects signals back through the DUT to the first port, enabling the VNA to measure transmission response indirectly through reflection measurements, thereby eliminating the need for direct simultaneous access to both ports

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the conventional mechanical connection requirement (physical access to both ports) with a signal processing approach using time gating. The time gating algorithm processes the reflected signal to extract transmission response characteristics, substituting physical accessibility requirements with computational signal separation

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If simultaneous access to both ports of DUT is required, then measurement precision is improved, but ease of operation worsens

Engineering Contradiction:

Improvetransmission response measurement accuracyVSAvoidport accessibility requirement

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

Instead of measuring transmission directly by injecting signals at one port and receiving at the other (conventional approach), the patent inverts the measurement approach by using reflection measurements at the first port with a known termination at the second port. The transmission response is derived from the reflected signal characteristics, effectively measuring 'the other way round' to achieve the same goal

Inventive Principle:

Principle #13The other way round (Inversion)

3Ease of operation

If time gating is applied to isolate reflection data, then ease of operation is improved, but measurement precision requirements worsen

Engineering Contradiction:

Improvesingle-port measurement capabilityVSAvoidreflection response isolation accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The known reflective termination is prepared in advance at the second port of the DUT. This pre-configured termination provides a known reflection characteristic that serves as a reference for the time gating process, enabling accurate isolation of transmission response data from the measured reflection signal

Inventive Principle:

Principle #10Preliminary action

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 enables the determination of the transmission response of the DUT even when one port is inaccessible, providing an accurate and efficient method for characterizing the device's performance across a range of frequencies.

Implementation Method 1

time gating the measured reflection response to isolate reflection data associated with the known reflective termination from the measured reflection response

Methodology Applied

Scientific EffectTime gating:

Data Source

PatentUS7170297B1Transmission response measurement system and method of using time gating

Publication Date: 2007.01.30 KEYSIGHT TECHNOLOGIES INC

AI summary

A method and a measurement system determine a transmission response of a device under test (DUT). The method includes measuring a reflection response from a first port of the DUT while a known reflective termination is on a second port of the DUT, and time gating the measured reflection response to produce a gated reflection response that is the transmission response of the DUT. The measurement system includes a vector network analyzer, a controller, a memory and a computer program. The computer program includes instructions that implement measuring the reflection response from the first port of the DUT, and further implement time gating the measured reflection response. The time gating isolates reflection data associated with the known reflective termination from the measured reflection response.