Portable RF Probe for Antenna Pattern Measurement
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Solution Overview
Problem
Current methods for monitoring transmitter output powers over the air are costly and cumbersome, particularly when testing radio frequency (RF) transmitters in the field, as existing designs are not designed for field use and are often laboratory-bound.
Innovation Solution
A small, unobtrusive probe system capable of being placed near RF transmitters, comprising an integrated broadband antenna, RF attenuator, demodulating logarithmic amplifier, and operational amplifier, which measures antenna pattern without distorting the RF signal and sends results to a remote location for analysis, allowing for over-the-air testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing measurement systems are used for over-the-air transmitter testing, then measurement capability is provided, but the systems are costly and cumbersome
Solution Approach 1:
The measurement system is segmented into a portable probe unit and a remote analysis system. The probe contains only the essential components (antenna, attenuator, detector, logarithmic amplifier) needed for signal measurement, while the complex analysis functions are separated and performed remotely. This segmentation reduces the complexity and cost of the field-deployable probe while maintaining measurement precision.
Solution Approach 2:
A portable probe serves as an intermediary device between the transmitter under test and the remote analysis system. The probe captures the RF signal, performs initial processing (attenuation, detection, logarithmic amplification), and transmits the processed data remotely. This intermediary approach allows complex measurements to be made without requiring the full measurement system to be present at the test location.
2Measurement precision
If measurement probe is placed close to transmitter for accurate measurement, then signal strength is sufficient, but the probe may distort the antenna pattern
Solution Approach 1:
The probe is designed with highly directional antenna characteristics that concentrate its sensing capability in a specific direction toward the transmitter. This local quality allows the probe to detect signals accurately from the transmitter while minimizing its impact on the overall antenna pattern of the device under test. The probe's small size and targeted orientation reduce its disruptive effect on the electromagnetic field.
Solution Approach 2:
The system replaces physical proximity-based measurement with a processed signal approach. Instead of relying solely on the probe's physical position and direct signal reception, the system uses the logarithmic amplifier to process the signal strength information and the remote system to analyze the data. This substitution allows for accurate measurement while maintaining a greater effective distance, reducing the probe's impact on the antenna pattern.
3Measurement precision
If laboratory-based measurement systems are used, then accurate measurements are obtained, but the systems cannot be deployed in field environments
Solution Approach 1:
The measurement system transitions from a static laboratory-based setup to a dynamic portable probe that can be deployed in various field environments. The probe is designed to be mobile and adaptable to different locations, while the remote analysis system provides the computational power needed for accurate measurements. This dynamic configuration allows the system to maintain measurement precision while gaining field deployment capability.
Solution Approach 2:
The portable probe is designed as a universal measurement device that can be deployed in both laboratory and field environments. It incorporates essential measurement functions (signal reception, attenuation, detection, logarithmic amplification) that work across different settings. The remote analysis capability further enhances universality by allowing the same probe to be used in various locations without requiring location-specific equipment.
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
Enables cost-effective, accurate, and efficient monitoring of transmitter signal power levels in various environments, beyond laboratory settings, facilitating diagnostic metrics like antenna patterns and path loss without affecting the emission pattern.
Implementation Method 1
an integrated broadband antenna adapted to receive a transmitted radio frequency ('RF') signal energy
Implementation Method 2
an RF attenuator configured to vary a maximum input power level of the transmitted RF signal energy
Implementation Method 3
a demodulating logarithmic amplifier configured to convert the RF signal energy received by the integrated broadband antenna to a decibel-scaled voltage signal
Implementation Method 4
an operational amplifier configured to invert and upscale the decibel-scaled voltage signal of the demodulating logarithmic amplifier
Data Source
AI summary
A system adapted for use with an electromagnetic transmitter and receiver system is provided comprising an electromagnetic transmitter and receiver system comprising an antenna, wherein the electromagnetic transmitter and receiver system is adapted to produce a transmitted signal for antenna pattern measurement which is transmitted through the antenna; a case located in proximity to the electromagnetic transmitter; at least one measurement probe disposed inside the case without changing the antenna's emission pattern, wherein the case, with the probe dispose therein, is placed no closer to the antenna than a limitation on the transmitter and receiver system component comprising a dynamic range associated with radio frequency energy received by the probe from the antenna; and an output section adapted to send results from the antenna pattern measurement received by the probe to a remote location away from the transmitter and receiver system for recording and analysis, the analysis comprising producing an antenna pattern measurement for the transmitter and receiver system.