MIL-STD-461 RE103 Radiated Emissions EMC Testing
As a leader in EMC regulatory compliance testing, Keystone Compliance assists electronic equipment manufacturers with MIL-STD 461 EMC testing. Meeting the IEC, EN, and other MIL-STD-461 testing requirements can be challenging. Not only do we understand the challenges, but we help guide companies through the process.
Keystone’s EMC testing engineers streamline the process and assist companies to achieve the compliance they require. Our MIL-STD-461 test engineers work with clients to quickly develop appropriate and concise test plans. Additionally, we are in constant communication throughout the entire test process.
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Summary of MIL-STD 461 Unintentional Radiator Compliance Testing
MIL-STD-461 standard test method RE103 is used as an alternative for conducted emissions CE106. This is only when testing transmitters with their intended antennas. The military standard test is met if the emissions do not exceed the applicable RE102 limit in transmit mode.
Military standard test method CE106 is the preferred requirement unless the equipment or subsystem design characteristics preclude its use. Radiated emissions 103 test is the preferred method for systems using active antennas or when the antenna impedance has a non-standard impedance curve.
The MIL-461 requirement is applicable from 10 kHz to 40 GHz. It is not applicable within the bandwidth of the EUT transmitted signal or within 5% of the fundamental frequency, whichever is larger.
For Navy shipboard applications with peak transmitter power greater than 1 kW, the 5% frequency exclusion is increased by an additional 0,1% of the fundamental frequency for each dB above 1 kW of peak power.
Scope of Unintentional Radiator Device Testing
The equipment is tested to an upper-frequency limit. This is based on the highest frequency generated or received by the EUT. For systems with the frequencies generated or received less than 1 GHz, the upper-frequency limit will be 20 times the highest frequency or 18 GHz.
For systems with frequencies generated or received greater than or equal to 1 GHz, the upper-frequency limit will be 10 times the highest frequency or 40 GHz. Lastly, for equipment using a waveguide, the requirement does not apply below eight-tenths of the waveguide’s cutoff frequency.
Harmonics and all other spurious emissions are to be at least 80 dB down from the level at the fundamental. This excludes second and third harmonic frequencies.
The second and third harmonics are suppressed to a level of -20 dBm or 80 dB below fundamental. The harmonics are suppressed with whichever frequency requires less suppression. For Navy shipboard applications, the second and third harmonics are suppressed to -40 dBm. Except if the duty cycle of the emissions are less than 0.2%, then the limit is relaxed to 0 dBm.
Data presented after the emission test is as follows:
- Tabular data showing fundamental frequency and frequency of all harmonics and spurious emissions measured, the measured power monitor level and the calculated ERP of the fundamental frequency, the ERP of all spurious and harmonics emissions measured, dB down levels, and all correction factors including cable loss, attenuator pads, amplifier gains, insertion loss of rejection networks and antenna gains.
- The relative dB down level is determined by subtracting the level from that recorded.
MIL-461 Standard Testing Procedures for RE103 EMC Testing
The radiated emissions test procedure is used to verify that radiated spurious and harmonic emissions from transmitters do not exceed the specified requirements. Furthermore, the test procedure is conducted as follows:
- The measurements are performed in the far-field of the transmitting frequency. The measurement system integrity is then checked. This is done by calibrating a signal level from the signal generator through the system check path at a midband fundamental frequency.
- Next, the equipment under testing is turned on and allowed sufficient time for stabilization. This is done by tuning the EUT to the desired frequency. For transmitters where a power monitor can be inserted, the modulated transmitter power output is measured using a power monitor while keying the transmitter.
Expert MIL-STD-461 Radiated Emissions EMC Compliance Testing
Keystone Compliance can accommodate fixed, mobile and portable devices of all sizes. In addition to EMC electromagnetic compatibility laboratory testing, Keystone has a full scope of expertise including environmental and package testing such as vibration, accelerated aging, and ingress protection. Our team strives to give our customers more time and energy on product development instead of testing.
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For more information on general MIL-461 compliance and test standards, please visit the links below: