Military EMI Filters

Captor Corporation is the most trusted name in electromagnetic interference (EMI) filters. Since 1965, we have provided solutions for military and aerospace applications. Our state-of-the-art manufacturing facility allows us to keep our sales, production, and engineering services under one roof.

Unlike many competitors that offer “off-the-shelf” parts, Captor provides tailor-made products to meet our customers’ precise specifications. As an industry leader in custom EMI filter manufacturing, Captor offers quick delivery of competitively priced components.

In addition to our custom EMI filters, Captor also manufactures standard COTS-MIL EMI filters that meet RTCA/DO-160 and MIL-STD-461 regulations.


Captor Corporation manufactures several different types of COTS MIL-STD-461 EMI filters. All our products can withstand harsh environments commonly found in military operations.

Per MIL-STD-461 regulations, each EMI filter provides maximum capacitance to ground limits of 50Hz to 400Hz. Our military EMI filters are also suitable for Navy use as they can mitigate conducted emissions between 10kHz and 10MHz.

The main difference between each of the Captor COTS-MIL EMI filters is the design features incorporated in each to meet the demands of the power line it is being used for.

Captor manufactures four primary types of EMI filters. The COTS-MIL EMI filters can include:

  • Circuit Breakers
  • Metal Oxide Varistors
  • Military Connectors for I/O Connection (upon request)

We are proud to announce a new series of COTS DC AND AC single-phase EMI filters. We also offer three-phase Wye EMI filters and three-phase Delta EMI filters for MIL-STD-461 applications.

COTS MIL-STD-461 Single Phase EMI Filters

Designed for single-phase power lines, the COTS MIL-STD-461 EMI filters are applicable for DC applications and can mitigate conducted emissions according to MIL-STD-41 CE102 requirements.

The COTS power line filters comply with all applicable commercial, industrial, and military standards while meeting the mandated electrical requirements.

According to MIL-STD-461 standards for Navy applications, each EMI filter adheres to the maximum capacitance to ground limits for 50Hz and 400Hz power line frequencies.

Certifications of Captor’s single-phase EMI filters include:

  • AS9100 D
  • ISO 9000:2015
  • IPC 610
  • IPC-620
  • J-STD-001

COTS MIL-STD-461 Three-Phase Wye EMI Filters

The COTS MIL-STD-461 EMI filter meets the requirements for three-phase Wye power lines. According to MIL-STD-461 CE012 standards, the COTS filter can mitigate conducted emissions from 10KHZ to 10MHz.

Harsh environmental conditions are not a threat to the mechanical construction and encapsulated assemblies of the EMI filter. The protection makes the filter conducive to all ground, air, and sea applications.

The EMI filter assemblies incorporate line to ground feed-through capacitors to maintain filter attenuation up to 1GHZ. Additional shielding isolates both the input and output compartments.

The alternating current (AC) voltage for three-phase Wye EMI filters is 254 V to 440 V. The frequency range of all filters is 50 Hz to 400 Hz. Captor offers the following three-phase Wye EMI filters with varying currency capacities:

  1. A-10903-05: 5 ampere current
  2. A-10903-15: 15 ampere current
  3. A-10903-30: 30 ampere current
  4. A-10903-50: 50 ampere current

120/208 VAC COTS MIL-STD-461Three-Phase Delta EMI Filters

Three-phase EMI filter use is applicable with 120/208 VAC Delta power lines and built to mitigate conducted emissions according to MIL-STD-461 CE102 specifications.

The alternating current (AC) voltage for three-phase Delta EMI filters is 120 V to 208 V, and the frequency range is 50 Hz to 400 Hz for all filters. Current capacities vary for the following Captor EMI filters:

  1. A-10901-05: 5 ampere current
  2. A-10901-15: 15 ampere current
  3. A-10901-30: 30 ampere current
  4. A-10901-50: 50 ampere current

254/440 VAC COTS MIL-STD-461 Three-Phase Delta EMI Filters

When working with 254/440 VAC Delta power lines, we recommend the MIL-STD-461 three-phase Delta EMI filter. The COTS filter can mitigate conducted emissions according to MIL-STD-461 CE102 standards.

The alternating current (AC) voltage for three-phase Delta filters is 254 V to 440 V with a frequency range of 50 Hz to 400 Hz. Captor offers the following three-phase Delta EMI filters:

  1. A-10902-05: 5 ampere current
  2. A-10902-15: 15 ampere current
  3. A-10902-30: 30 ampere current
  4. A-10902-50: 50 ampere current

COTS MIL-STD-461 Single Phase EMI Filters

COTS MIL-STD-461 Single Phase EMI Filters

Designed for single phase power lines. This style can be used for DC applications as well.

COTS MIL STD 461 Three Phase Delta EMI Filter

COTS MIL-STD-461 Three-Phase Wye EMI Filters

Designed for three phase Wye power lines.

120/208VAC COTS MIL-STD-461 Three-Phase Delta EMI Filters

120/208VAC COTS MIL-STD-461 Three-Phase Delta EMI Filters

Designed for 120/208VAC Delta power lines.

254/440VAC COTS MIL-STD-461 Three-Phase Delta EMI Filters

254/440VAC COTS MIL-STD-461 Three-Phase Delta EMI Filters

Designed for 254/440VAC Delta power lines.

Our COTS-MIL EMI filters can be supplied with circuit breakers, Metal Oxide Varistors, and military connectors for I/O connections upon request.

MIL-COTS Filters CAD Catalog

Custom Military EMI Filters

At Captor Corporation, our high-quality EMI filters meet the stringent design regulations for military applications, including Military Standards (MIL-STD), Military Performance Specifications (MIL-PRF), and Radio Technical Commission for Aeronautics (RTCA).

Each of our EMI military filters meets the following specifications:


The United States Department of Defense regulates MIL-STD-461 system-level emission testing standards. Military suppliers, such as Captor, must prove compliance determination on all products.

Our EMI military filters can adequately function in electromagnetic (EM) environments without releasing EM energy that could interfere with nearby devices.


This standard governs the testing of all products containing printed circuit boards (PCBs). Specifically, MIL-STD-202  provides guidelines for testing electronic devices to ensure they can withstand the potentially harmful effects of the environment in which they will operate, including the effects of the surrounding military applications.


Military defense contractors must adhere to MIL-STD-220 regulatory standards for all products. Captor follows component or system-level testing protocols in all military EMI filters. The units must meet certain environmental condition thresholds that could be evident in their operational lifespan.

The military standard testing protocol, MIL-STD-220, measures insertion loss of both single circuit and multiple circuit EMI and radio frequency (RF) filters. Feed-through suppression capacitors at 10GHz and below in 50 ohm systems are also regulated.

Since 1952, the MIL-STD-220 military standard has provided performance specifications for various types of EMI filters.


The MIL-PRF-15733 military performance standard covers the EMI filter requirements and testing specifications for low-pass filters and capacitors that are used for suppressing EMI and radio frequency signals.

All military EMI filters manufactured by Captor Corporation meet or exceed these strict standards.


RTCA/DO-160 is a testing protocol enacted by the Radio Technical Commission for Aeronautics (RTCA). All prominent aerospace manufacturers and avionics distributors follow the standard for airborne components.

The purpose of the stringent testing guidelines is to recreate a particular environmental condition that might occur during the flight to ensure product safety and performance.

Military EMI Filters Engineering Capabilities

At Captor Corporation, engineers design all our EMI filters to meet or exceed the following specifications:

  • Insertion Loss: 0 to 100 dB
  • Voltage Rating: 0 to 400 VDC and 0 to 480 VAC (higher ratings available upon request)
  • Current: 0 to 400 amps (higher ratings available upon request)
  • Frequency: DC frequencies up to 400 Hz (higher ratings available upon request)
  • Operating Temperatures: -55ºC to 85ºC
  • Storage Temperatures: -55ºC to 105ºC

Our experienced team offers technical support through all stages of development, including initial product design.

We offer in-house environmental testing and can provide terminated cable assemblies for military applications. All EMI filters and components are AS9100D, including ISO 9000:2015 certified, and are certified according to IPC 610, IPC-620, and J-STD-001 standards.

Captor offers extensive manufacturing expertise in EMI/HEMP filters while offering optimal development services.

Captor Corporation for Military Standard and Custom MEI Filters

Captor adheres to all regulations to ensure the accurate and precise performance of our broad range of EMI filters. We follow all specifications regarding testing methods, screening, mechanical configurations, and electrical performance of all components.

Our EMI filters are ideal for defense and aerospace applications because of our strict adherence to military standards and testing protocols.

View our catalog of products and request information to learn more about the broad range of EMI filters that Captor Corporation offers. Contact us with any questions about our products and to discuss your specific needs. Our team looks forward to designing a solution that far exceeds your expectations.