MIL-STD-461G RS103: Radiated Susceptibility, Electric Field

Standard Overview Products Used in Testing Related Compliance Standards

Standard Overview

MIL-STD-461G RS103 is used to verify the ability of the EUT and associated cabling to withstand electric fields. MIL-STD-461G RS103 is applicable for equipment and subsystem enclosures and all interconnecting cables. MIL-STD-461G RS103 is applicable as follows:

Frequency Range	Applicability
2 MHz to 30 MHz	Army, Navy and optional for all others
30 MHz to 18 GHz	All
18 GHz to 40 GHz	Optional for all

Test Equipment

Signal Generator – Creates signals and modulations for the amplifier.
Power Amplifier – Takes signal, amplifies it sometimes greater than 1,000,000 times original power (0dbm going into 1000 W).
Low Loss Cables – Interconnect all coax equipment after the amplifier.
Dual Directional Coupler – Couples off-nominal values of forward and reverse power (typically by 40 dB or 50 dB).
Power Sensors – Measures coupled power from dual directional coupler for monitoring (may need attenuator between the forward coupled port and power sensor to avoid damage).
Power Meter – Dual channel, displays power sensor reading in dBm or Watts.
Tripod – Holds up the radiating antenna, non-metallic.
Radiating Antenna – Transducer which emits RF power into space from the signal source.
Electric Field Probe – Measures e-field strength (V/m) on X, Y, Z axes, and composite and returns data via fiber cable.
Fiber Optic Communication Link – Non-conductive communication link between field probe and probe interface.
Probe Interface – Provides both power and communication to the e-field probe.

Procedures

The test procedures shall be as follows:

a. Turn on the measurement equipment and EUT and allow sufficient time for stabilization.
b. Assess the test area for potential RF hazards and take necessary precautionary steps to assure the safety of test personnel.
c. EUT testing:
- (1) Perform testing over the required frequency range with the transmit antenna vertically polarized:
  - (a) Set the signal source to 1 kHz pulse modulation, 50% duty cycle. Verify that the modulation is present on the drive signal for each signal generator/modulation source combination. Ensure that the modulation frequency, waveform, and depth (40 dB minimum from peak to baseline) are correct. Using appropriate amplifier and transmit antenna, establish an electric field at the test start frequency. Gradually increase the electric field level until it reaches the applicable limit.
  - (b) Scan the required frequency ranges in accordance with the rates and durations specified in Table III. Maintain field strength levels in accordance with the applicable limit. Monitor EUT performance for susceptibility effects.
  - (c) Ensure that the E-field sensor is indicating the field from the fundamental frequency and not from the harmonics.
- (2) If susceptibility is noted, determine the threshold level in accordance with 4.3.10.4.3.
- (3) Repeat the testing above 30 MHz with the transmit antenna horizontally polarized.
- (4) Repeat 5.21.3.4c for each transmit antenna position required by 5.21.3.3c.

Test Setup

Frequency	Amplifier	Antenna	DUT Placement	Max DUT Dimension/Size at Specified Ant. Dist. (m)
10 kHz – 25 MHz	5000 W	10 kHz – 30 MHz	Between Elements	≤ 0.90 x 2.10 x 2.90
10 kHz – 30 MHz	150 W	10 kHz – 30 MHz	Between Elements	≤ 0.80 x 0.50 x 0.50
10 kHz – 100 MHz	500 W	10 kHz – 100 MHz	Between Elements	≤ 0.36 x 0.46 x 0.36
30 MHz – 220 MHz	5000 W	25 – 1000 MHz	Dependent on Shielded Enclosure Parameters
30 MHz – 225 MHz	16000 W	26 – 1000 MHz	1 meter	0.43
220 MHz – 1 GHz	1000 W	80 – 1000 MHz	1 meter	0.53
800 MHz – 4.2 GHz	350 W	800 MHz – 5 GHz	1 meter	0.31
2.5 – 7.5 GHz	300 W	2 – 10.6 GHz	1 meter	0.31
4 GHz – 8 GHz	200 W	4 – 8 GHz	1 meter	0.24
4 GHz – 8 GHz	60 W	4 – 8 GHz	1 meter	0.24
7.5 – 18 GHz	300 W	7.5 – 18 GHz	1 meter	0.5
18 GHz – 26 GHz	40 W	18 – 26.5 GHz	1 meter	0.32
26 GHz – 40 GHz	40 W	26.5 – 40 GHz	1 meter	0.19

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