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What is a Magnetic Flux Channel Antenna?

MFC

What is a Magnetic Flux Channel Antenna?

JEM Engineering has developed a series of antennas called Magnetic Flux Channel Antennas, or, as they are nicknamed, MFC Antennas

Most conventional antennas are made with conducting metals and dielectrics that allow electric charge to vibrate at radio frequencies. For example, in modern communications equipment such as cell phones, the electric charge vibration frequencies (GHz radio frequencies) can be several billion cycles per second. The antenna structure establishes a path to which the vibrating electric charges are confined and further define the antenna pattern they produce. However, when a very low-profile antenna is desired, the close proximity of metal structure to a conventional antenna causes poor performance unless cavities or other bulky structures are allowed. 

JEM Engineering’s MFC antennas do not utilize electric charge to achieve radiation. Instead, the magnetic flux that resides in the MFC core shapes and supports an efficient form of magnetic polarization current in a specially designed flux channel. The MFC core is an inhomogeneous and anisotropic construction whose design and fabrication are proprietary to JEM Engineering. This groundbreaking technology allows for closer proximity and integration within conductors, which cannot be achieved by conventional antennas. 

Unlike conventional antennas, the MFC may be placed directly on, or even within, conducting structure with no ill-effects on radiation or impedance match performance. For communications in the VHF/UHF bands (30 MHz to 3 GHz) MFC antennas can provide equivalent performance to conventional.

In recent years, the company has incorporated MFC technology into a variety of different antenna designs, including those that fulfill specific conformal/low-profile requirements. The antennas are typically made from high-hesitivity, low-loss material.

The development of these antennas originated from research conducted under the SBIR program.

Antennas: A History


  

Antennas: A History

In honor of our seventeenth anniversary, we invite you to take a look at some major developments in antenna research and trends over the past century.

1920s: Yagi-Uda Antenna

In 1926, Japanese inventor Shintaro Uda, with the help of his colleague, Hidetsugu Yagi, developed the Yagi-Uda antenna. Modern versions of this antenna are used on high frequency (HF), very high frequency (VHF), and ultra high frequency (UHF) bands due to its characteristically high gain.

The directional antenna is primarily an array of linear dipoles with one driven element serving as the feed while additional elements act as “parasitic.” While the feed element is connected to the transmitter or receiver with a transmission line, the additional elements are unattached. The purpose of these parasitic elements (or passive radiators) is to modify the radiation pattern of the radio waves emitted by the driven element, directing them in a beam in one direction. This increases the the antenna’s directivity and consequently, its gain.

Today, this style of antenna is commonly known as the “beam antenna” or the “parasitic array.”  However, many still refer to it as the “Yagi antenna.” This is perhaps due to the fact that while Uda was mainly responsible for the antenna’s invention, it was Yagi who helped popularize the antenna in the United States.

1930s: Horn Antenna

A relatively simple and widely used antenna, the horn antenna, can date its origins back to the late 1800s. However, it wasn’t until decades later, during the World War II era, that it became popular. In 1938, American inventor Wilmer Lanier Barrow invented the first modern horn antenna, following his invention of the waveguide in 1936. 

Horns can be used in a variety of different applications due to their ease of use and their ability to achieve large gain. As an added bonus, they feature relatively simple construction, which makes them generally cost-effective. An example of an efficient, yet simply constructed modern horn antenna is the JEM-440.

The modern electromagnetic horn can take many different forms, four of the most popular being E-plane, H-plane, pyramidal, and conical. The differences in type, direction, and amount of taper are variables that augment a horn antenna’s overall performance as a radiator.

Dish Antennas

1960s: Dish Antennas

The “satellite dish” is perhaps the most recognizable type of antenna among consumers. It’s classified as parabolic reflector, a type of antenna which gets its name from its curved surface (parabola). Although the earliest version of the parabolic reflector antenna was developed in 1888 by German physicist Heinrich Hertz, it wasn’t until the 1960s that these types of antennas became commonplace.

Besides satellite television, parabolic antennas are used as high-gain antennas for point-to-point communications, in applications such as microwave relay links that carry telephone and television signals between cities, wireless WAN/LAN links for data communications, and satellite communications. These antennas have also been useful in spacecraft communications for decades.

Additionally, parabolic antennas are widely used as radar antennas for locating ships, airplanes, and guided missiles. 

1970s: Microstrip Antennas

Although they originated 1953, microstrip antennas started garnering plenty of attention in the 1970s. Also known as “patch antennas,” they are extremely useful in aircraft, spacecraft, satellite, and missile applications, as well as mobile radio and wireless communications, due to their characteristically low profile. They are also inherently lightweight, inexpensive to manufacture, and easy to install. The RFD-8696 is an example of a very versatile patch antenna.

The defining characteristic of the modern microstrip antenna is that they can be printed directly onto a circuit board. 

1980s: Planar Inverted-F Antenna (PIFA)

A form of patch antenna, the Planar Inverted-F antenna (PIFA) is a common component in handheld devices. It gets is name from it’s shape, which resembles an inverted “F.”

The PIFA resonates in an omnidirectional pattern. More importantly, it does so  at a quarter-wavelength, allowing manufacturers to increasingly reduce the amount of space the component needs to occupy within a mobile device. 

PIFAs also have favorable SAR properties. SAR is a a function of the electrical conductivity, which measures how transmitted RF energy is absorbed by human tissue. It stands for “Specific Absorption Rate.”

All of the aforementioned antenna designs are still being used today. In fact, because there have been numerous developments that improve upon their designs, they have even become more useful than they were when they were first invented. As antenna design continues to evolve at an even faster pace, it is important to quickly and efficiently test the resulted products

 

An Introduction to Jammers

An Introduction to Jamming Antennas

While “interference” generally describes unintentional forms of disruption during wireless communications, “jamming” describes the deliberate interference with or blocking of such communications.

As the name suggests, jamming antennas, (aka jammers) are specifically used to interfere with radio noise or signals. In electronic warfare (EW) these interference are meant to disrupt control of a battle. For example, jammers radiate interfering signals toward an opponent’s radar, blocking the receiver with highly concentrated energy signals. 

The two main jamming techniques are noise techniques and repeater techniques. Spot jamming, sweep jamming, and barrage jamming are the three most common types of noise jamming, whereas DRFM jamming is the most common type of repeater jamming. 

Spot jamming is a form of noise jamming, where a jammer focuses all of its power on a single frequency, rendering the technique ineffective against a frequency-agile radar. Sweep jamming is the process of shifting a jammer’s full power from one frequency to another. This “sweeping” motion jams multiple frequencies in quick succession, although not all at the same time. Barrage jamming is the jamming of multiple frequencies at once by a single jammer. The main drawback of this technique is that the jammer spreads it’s power across multiple frequencies, making it comparatively less powerful at a single frequency.

Digital frequency radio memory, or DRFM, is a repeater technique that confuses a radar by altering and re-transmitting received radar energy. For example, by changing the delay in transmission of pulses, the jammer can alter the range the radar detects and creating false targets. Many jamming antennas use these types of techniques.

At present, there are several countermeasures against jamming. Similar to jamming techniques, these countermeasures allow for varying levels of effectiveness. Additionally, specifically designed, anti-jam antennas have become available. As new RF technologies emerge, so do developments in electronic warfare.

2019 Best of Laurel Awards

Nancy Lilly, CEO of JEM Engineering, holding The 2019 Best of Laurel Award
JEM Engineering has been selected for the 2019 Best of Laurel Award, pictured above, is CEO, Nancy Lilly, holding the award plaque.
JEM Engineering is among a small group of companies that have won the Best of Laurel Award for ten consecutive years. This distinction
has qualified JEM Engineering for the 2019 Laurel Business Hall of Fame.

Rapid RF Testing Services

At JEM Engineering, we understand that accurate measurement of antenna electrical performance is critical. That’s why we offer a range of rapid testing services from 50 MHz to 40 GHz for antenna, microwave and communication systems.

Our Testing Services allow for:

  • Complete tests in minutes instead of days
  • Frequency ranges from 50 MHz to 40 GHz, covering standards such as Bluetooth™, WiFi, WiMAX, GPS, cellular, and more!
  • Capabilities Including:
    • Radiation patterns
    • Antenna gain and efficiency
    • Axial ratio
    • Human body interaction effects
  • Multiple test chambers to fit your needs
  • Variety of data format options, patterns and plots, including:
    • 2D and 3D Radiation patterns from our Spherical Near-Field (SNF) Chamber
    • Swept gain and efficiency
    • ASCII data
  • Data files can be processed using a variety of software, such as:
    • MATLAB®
    • MathCAD®
    • EXCEL®
  • Data can be saved directly and securely to a customer’s own hard drive on-site

Our Location

JEM houses multiple RF test chambers at our facility in Laurel, MD, centrally located between Baltimore and Washington, D.C, and convenient to Dulles International, BWI, and Reagan Washington National airports.

Customers testing at JEM have the advantage of working with our knowledgeable and experienced onsite RF technicians and engineers, who provide guidance and support to the testing experience and can assist with data analysis and interpretation.

Our Promise

We have the highest commitment to your business’s proprietary designs and trade secrets, keeping everything you give us – as well as resulting test data – under careful lock and key. Furthermore, we promise to provide the most experienced test technicians and antenna engineers, providing you with the best value of high accuracy antenna testing in the industry.

Get A Rapid Antenna Testing Quote Now

To learn more and to find out if rapid RF testing from JEM Engineering is a good fit for you project, contact us at (301) 317-1070 or request a quote online for antenna testing services.


JEM Engineering Quality Commitment Guarantee
JEM has decades of experience in the custom antenna design and development and RF testing services industry. We promise customers a full 100% satisfaction guarantee of products and services, including rapid testing services for government and commercial applications.
At JEM, we are dedicated to improving performance, efficiency and overall business of our customers. Because of this dedication, we are always innovating alongside our customers to improve current products and tackle challenges.

More about JEM Engineering
JEM Engineering’s team boasts over 150 years of combined experience, allowing it to take an antenna concept all the way through to full-scale production. Not only do we deliver quickly, we also extend our full satisfaction guarantee to all of our customers on all of our products, as well as our services. We are a 100% women owned small business.

Honoring Black Engineers

JEM Engineering is a minority owned company and in honor of Black History Month we would like to shine light on two Black engineers who have made an impact in the world of engineering.


 

Elijah McCoy was born in Colchester, Ontario, Canada on May 2, 1844. His parents were George and Emillia McCoy, former slaves from Kentucky who escaped through the Underground Railroad. George joined the Canadian Army, fighting in the Rebel War and then raised his family as free Canadian citizens on a 160-acre homestead.

At an early age, Elijah showed a mechanical interest, often taking items apart and putting them back together again. Recognizing his keen abilities, George and Emillia saved enough money to send Elijah to Edinburgh, Scotland, where he could study mechanical engineering. After finishing his studies as a “master mechanic and engineer” he returned to the United States which had just seen the end of the Civil War and the emergence of the “Emancipation Proclamation.”

Elijah moved to Ypsilanti, Michigan but was unable to find work as an engineer due to racial barriers. He was thus forced to take on a position as a fireman and oilman on the Michigan Central Railroad. As a fireman, McCoy was responsible for shoveling coal onto fires which would help to produce steam that powered the locomotive. As an oilman, Elijah was responsible for ensuring that the train was well lubricated. After a few miles, the train would be forced to stop, and he would have to walk alongside the train applying oil to the axles and bearings.

In an effort to improve efficiency and eliminate the frequent stopping necessary for lubrication of the train, McCoy set out to create a method of automating the task. In 1872 he developed a “lubricating cup” that could automatically drip oil when and where needed. He received a patent for the device later that year. The “lubricating cup” met with enormous success, and orders for it came in from railroad companies all over the country. Other inventors attempted to sell their own versions of the device, but most companies wanted the authentic device, requesting “The Real McCoy.”

 

 

Dr. Aprille Ericsson was born in Brooklyn, New York in 1963 and raised in the Bedford Stuyvesant neighborhood of Brooklyn. In junior high she won second place in the science fair, played on the girls’ basketball team and was a member of the science club, honors club and school band.

Although Aprille passed all entrance exams for New York’s technical high schools, she chose to move to Cambridge, Massachusetts to live with her grandparents and attend the Cambridge School of Weston. In high school she participated in both citywide and intramural softball and basketball leagues, while earning high scholastic honors. She was also accepted into the rigorous academic enrichment program, UNITE (now known as the Minority Introduction to Engineering, Entrepreneurship and Science or MITE.)

Dr. Aprille Ericcson graduated high school with top honors and attended the Massachusetts Institute of Technology (MIT) where she was involved in several research projects with the applied Physics Laboratory that included the development of a fiber optic laser gyroscope, and the creation of a database for EVA neutral buoyancy data calculated at the NASA Johnson Space Center.

After earning a Bachelor of Science degree in Aeronautical/ Astronautical Engineering at MIT, Dr. Ericcson attended Howard University in Washington, D.C. She became the first African- American woman to receive a Ph.D. in mechanical engineering at Howard University and the first female African-American to receive a doctorate in engineering from the NASA Goddard Space Flight Center. 

Discussing her internship at the NASA Goddard Space Flight Center during school, Dr. Ericcson explained how she was offered a full-time position there after obtaining her Ph.D., “That’s how I did it. Once you get your foot in the door and meet people, you can show them that you are capable of doing the type of work that’s done here.”

Her many honors include: The Women’s Network, Top 18 Women Who Will Change the World; Women in Science and Engineering for Engineering Achievement; National Technical Association, Top 50 Minority Women in Science and Engineering, 1996-97; NASA representative to the White House; and most recently in 2016, the Prestigious Washington Award.

 


More about JEM Engineering

JEM Engineering’s team boasts over 150 years of combined experience, allowing it to take an antenna concept all the way through to full-scale production. Not only do we deliver quickly, we also extend our full satisfaction guarantee to all of our customers on all of our products, as well as our services. We are a 100% women owned small business.

Product Spotlight: HSA-2438 Antennas


JEM Engineering’s HSA-2438 Antennas are Concealed and Low-Profile Antenna Products.

UHF MUOS SATCOM Antenna (HSA-2438)

The HSA‐2438 hybrid spiral antenna is designed for UFO and MUOS SATCOM band and vehicular use. The antenna operates on 244 – 270 MHz, 292 – 320 MHz, and 360 – 380 MHz and has been optimized for the MUOS bands. The unique pattern is designed for cardioid shaped gain overhead to 10 degrees in elevation where SATCOM links are more difficult to close. The hybrid spiral antenna can be mounted on a vehicle surface with no degradation to the pattern or VSWR and is ground plane independent.

 

Low Profile MUOS SATCOM Antenna (HSA-2438A)

The HSA-2438A Initially designed for flush mount on a tubular chassis mounting, this low-profile, compact spiral antenna is suitable for vehicular or airborne use. The pattern is designed for uniform gain overhead to 45 degrees in elevation. The hybrid spiral antenna can be flush mounted on a vehicle or airborne surface with little to no degradation to the pattern or VSWR. This rugged spiral can be equipped with a side or bottom mounted connector.

 

Conformal MUOS SATCOM Antenna (HSA-2438C)

 

The HSA-2438C is designed for a conformal airborne application operating in extreme environments, vibration, and speed. This low-profile, compact spiral antenna is suitable for vehicular or airborne use. The pattern is designed for uniform gain overhead to 40 degrees in elevation. The hybrid spiral antenna can be flush mounted on a vehicle or airborne surface with little to no degradation to the pattern or VSWR.  This rugged spiral can be equipped with a side or bottom mounted connector.

 

Low Profile MUOS SATCOM Antenna (HSA-2438LP)

 

HSA-2438 Initially designed for flush mount on a tubular chassis mounting, this low‐profile, compact spiral antenna is suitable for vehicular or airborne use. The pattern is designed for uniform gain overhead to 40 degrees in elevation. The hybrid spiral antenna can be flush mounted on a vehicle or airborne surface with little to no degradation to the pattern or VSWR. This rugged spiral has optional side or bottom mounted connectors.

 

JEM Engineering Quality Commitment Guarantee

JEM has decades of experience in the custom antenna design and development and RF testing services industry. We promise customers a full 100% satisfaction guarantee of products and services, including rapid testing services for government and commercial applications.

At JEM, we are dedicated to improving performance, efficiency and overall business of our customers. Because of this dedication, we are always innovating alongside our customers to improve current products and tackle challenges.


Request A Quote for Testing Services in the Tapered Antenna Test Facility (TATF) Chamber at JEM Engineering

Learn firsthand how JEM Engineering is dedicated to developing and producing top quality antennas for their customers. Contact JEM Engineering for a free consultation and a quote on testing your antenna in the TATF Chamber at JEM.


More about JEM Engineering

JEM Engineering’s team boasts over 150 years of combined experience, allowing it to take an antenna concept all the way through to full-scale production. Not only do we deliver quickly, we also extend our full satisfaction guarantee to all of our customers on all of our products, as well as our services. We are a 100% women owned small business.

Which testing chamber? TATF vs. SNF

JEM Engineering boasts two antenna testing chambers at our facility in Laurel, MD, within easy reach of both Baltimore and Washington DC.

Customers testing at JEM have the advantage of working with our knowledgeable and experienced RF technicians and engineers, who provide guidance and support to the testing experience, as well as assist with data analysis and interpretation. While our experts can easily determine which chamber is suitable for a particular test, it’s also helpful to know what each chamber’s capabilities are.

The TATF is ideal for testing over a variety of frequencies.

A Tapered Antenna Test Facility (TATF) Chamber provides powerful validation capabilities over a wide frequency range, allowing the testing of antennas and antenna systems for a variety of applications. Using these tools, we can measure radiation patterns, antenna gain (peak, average, max linear, min linear, H and V) and axial ratio from 80 MHz to 40 GHz.

Measurement accuracy is critical, and the TATF chamber offers accuracy of peak gain measurements ± 1.0 dB from 80 to 400 MHz, ± 0.7 dB from 400 MHz to 1 GHz, and ± 0.5 dB from 1 GHz to 18 GHz. The data analysis and reduction software supports a wide range of outputs, including radiation patterns and swept gain. Our engineers can also produce ASCII data files compatible with third party analysis tools such as MATLAB®, MathCAD® or EXCEL®

Test times depend on the number of frequency points taken, the number of angular steps measured, and the amount of noise correction applied. The max power at the input port of the PNA is +30 dBm; however, we can add a pad in line to allow gain much higher (as much as +110 dBm).

The SNF can test a smaller range of frequencies, but it can complete tests in as little as 15 minutes.

A Spherical Near-Field (SNF) antenna test chamber is the fastest facility available for full 4 pi steradian data collection. It uses an array of electronically scanned probes to scan a full 360-degree measurement plane, giving technicians the ability to complete measurements in minutes rather than hours.

This chamber can perform tests over frequencies from 400 MHz to 6 GHz, enabling testing of antennas for AMP, PCS, GSM, Bluetooth™, IEEE 802.11, GPS and other new and evolving wireless systems.

The spherical chamber at the testing facility at JEM can be customized to work for any antenna. While existing structures are in place that work with testing for most antennae, JEM Engineering also works with customers to custom design fixtures that will work to test any type of device.

The SNF Test Chamber can be used to test active devices, antennae with an amplifier or an attenuator, and even can be used to test a body worn or handheld device on a subject. By mounting the antennas in free space or on human subjects allows for the measurement of radiation patterns, efficiency, average gain, and any human body interaction to the radiating device. As with the TATF, our engineers can produce test information in a variety of formats.

*25dBi is the ceiling for gain measurements. A pad can be installed in our system to protect the equipment from saturation.

 

Request A Quote for Testing Services in the TATF or SNF at JEM Engineering

Learn firsthand how JEM Engineering is dedicated to developing and producing top quality antennas for their customers. Contact JEM Engineering for a free consultation and a quote on testing your antenna in the TATF and SNF Chambers at JEM.

Product Spotlight: The FPA-218

Product Spotlight: The FPA-218

The FPA-218 is vertically polarized, flat panel antenna which provides high‐level performance in a unique, low-profile design. It maximizes transmission/detection while taking up minimal space.

With an ultra-wide frequency range, this system is excellent for ELINT/SIGINT requirements over a broad band.

The ‐2 version provides a dual output and ‐3 provides a three output system.