Free Space Quasi Optical Transmission Loss Calibration for Radome Materials
Calibrate free-space quasi-optical benches with time-gated TRL standards to prevent radome transmission loss from breaching radar EIRP regulatory limits.
Insertion Loss Measurement
Meaning
Power attenuation tests quantify the signal degradation introduced by a component or material inserted into an active transmission path. An insertion loss measurement compares the transmitted power before and after the test object is placed between the signal source and the receiver. This evaluation determines whether a radome or filter meets the transmission efficiency requirements of a wireless module.
Engineers use this test to verify that the protective enclosure does not excessively weaken the transmitted or received signal.
Test Methodology
System characterization involves routing an RF signal through a coaxial cable or waveguide directly to a power sensor to establish a baseline. Executing an insertion loss measurement requires the technician to insert the device under test into this path and record the decrease in received power. This process is repeated across the entire operational frequency band to generate a continuous loss profile.
For free-space testing, the device under test is placed between two aligned horn antennas inside an anechoic chamber to isolate the transmission characteristics.
Equipment Calibration
Accurate results require neutralizing the losses of cables, adapters and connectors before collecting data from the device under test. During an insertion loss measurement, a vector network analyzer is calibrated using a standard kit to establish a reference plane. This calibration subtracts the systematic errors of the test bench from the final measurement data.
Without this step, cable loss or adapter mismatch would be incorrectly attributed to the device, leading to false failures during assembly testing.
Quality Assurance
Production line testing ensures that every manufactured radome or RF component meets the specification limits defined during the design phase. A standardized insertion loss measurement acts as a pass or fail gate for completed assemblies before they are packed for shipment to the customer. When the measured loss exceeds the specified threshold, the unit is routed to a diagnostics station to check for issues like air gaps, adhesive over-application or material contamination.
Keeping insertion losses below the limit is necessary to guarantee the specified operating range of the integrated product. Quality logs are automatically generated for each module, allowing the manufacturing team to monitor process stability and track long-term trends in material performance.