Antenna Engineering Blog

What is Beamforming?

The term beamforming refers to a method of directing a wireless signal towards a specific receiving device, whereas the alternative would be allowing the signal to spread in all directions from a transmitter the way it naturally would.

By focusing a signal in a specific direction, beamforming delivers higher signal quality to a receiver. This means information is transmitted faster and more accurately. Furthermore, this accuracy can be reached without boosting broadcast power.

Example of Radiation Pattern with

a Fixed Beamformer

Example of Radiation Pattern with

an Adaptive Beamformer

An antenna array is comprised of multiple radiating elements, each of which contributes an element pattern to the array’s radiation pattern. Each element pattern is a spatial distribution of RF power arising from the amplitude and phase of the RF signal at the element’s RF feed point. The array’s radiation pattern is determined by the coherent sum of all element fields, each which may be “weighted” by an additional amplitude and phase. Such weighted patterns exemplify beamforming in the array, whereby sidelobe levels and nulls are produced and controlled by adjusting the element weights.

Beamforming techniques loosely fall into two categories: conventional and adaptive.

Fixed beamforming generally describes a conventional technique where the antenna array pattern is obtained from fixed element weights that do not depend on the signal environment. Conversely, adaptive beamforming element weights that do depend on —and can adapt to— the signal environment via some feedback mechanism.

Adaptive beamforming, which was initially developed in the 1960s, uses a digital signal processor (DSP) to compute the complex weights using an adaptive algorithm, which then generates an array factor for an optimal signal-to-interference-plus-noise ratio (SINR). Basically, adaptive beamformers are designed to adjust to differing situations in order to maximize or minimize SINR, which helps measure the quality of wireless communication.

The average civilian experiences adaptive beamforming technology in their every day life. In fact, wireless carriers use adaptive beamforming to provide next-generation wireless communications (5G) and long-term evolution (LTE) services.

Antenna Miniaturization

As the phrase suggests, antenna miniaturization is the process of replicating an antenna’s functionality while reducing its physical size.

Over the past several decades, several studies have shown a direct correlation between the size of an antenna and its bandwidth and/or efficiency. Basically, it had been long since believed that the smaller the antenna, the smaller the bandwidth, and the lower the efficiency. In more recent years, however, this idea has become somewhat of a fallacy.

Technological advancements have greatly impacted antenna design, making it possible to miniaturize antennas without sacrificing performance. For example, JEM Engineering’s MBA-0145 is essentially the miniaturized version of the MBA-0127. Both antennas are multi-band (or HexBand) box-type antennas. Size and weight differences aside, the antennas are very similar in specifications.

	MBA-0127	MBA-0145
Dimensions (LxWxH)	16″ x 16″ x 2.3″	9″ x 9″ x 2.3″
Weight	9 lbs	3.6 lbs
VSWR	< 2.5 : 1	< 2.5 : 1
Frequency Band	410 – 500 MHz 820 – 960 MHz 1700 – 2200 MHz	410 – 500 MHz 820 – 960 MHz 1700 – 2200 MHz
Polarization	Right Hand Circular	Right Hand Circular
Power	50+ Watts	50+ Watts
Ground Plane	Independent	Independent
Connector	SMA Female	SMA Female

Why miniaturize?

One of the more obvious reasons is that lower profile antennas are easier to conceal and transport. This can be useful in ISR SIGINT/ELINT applications.

While antenna miniaturization has become more doable, there are still some limitations to this process. Just as it takes a combination of keen mechanical design and proficient electrical engineering to successfully miniaturize an antenna, it takes similar expertise to determine whether or not an antenna should be miniaturized or redesigned altogether, given its intended application. A trained team of experts usually performs a feasibility analysis before attempting to miniaturize an antenna.

Community Outreach

Since our inception, JEM Engineering has made it our objective to not only excel in delivering antenna solutions, but to also give back to the community.

This November, we have increased our community outreach efforts by donating more funds, as well as resources, to the following charities.

To learn more about the charitable events we have participated in, as well as the organizations we work with, please visit our Community Outreach page.

What is a Magnetic Flux Channel Antenna?

Years ago, JEM Engineering developed the Magnetic Flux Channel Antenna. Now, the company has a series of these types of antennas, 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 core of the magnetic flux channel antenna 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 the magnetic flux channel antenna originated from research conducted under the SBIR program.

Antenna History

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

1920s: Yagi-Uda Antennas

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 Antennas

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 Antennas (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

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.

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.

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.

STEM with JEM

Did you know that National STEM Day falls on the 8th of November each year? That’s because the abbreviation “NOV8” actually stands for “INNOVATE.”

STEM is all about innovation. The goal of STEM Day is to not only acknowledge those who work in fields related to Science, Technology, Engineering, and Mathematics, but also to encourage young minds to follow their passions and pursue such careers.

JEM Engineering is proud to have an extremely skilled and diverse group of individuals who make things happen! We asked our very own Matt Berry (Mechanical Engineer) and Anjali Bhattarai (Electrical Engineer) to talk about why they chose their career paths.

What is it about engineering that interests you?

M: Problem-solving. Also, the most satisfying thing about engineering is thought that the 3D models and design documents you spent time developing on your computer will eventually be held in your hand – your hard work has become a real thing. (Read more about the process of developing a product here.)

A: As an electrical engineer, I find the concept of energy very enticing. Every object in the universe requires energy to perform its activity. Having the opportunity to generate and control electrical energy is definitely the best part. There’s also the added benefit of working with high tech gizmos like cell phones and smartwatches before they hit the market.

Did you always know that you wanted to be an engineer? If not, what was your first career choice and what made you switch to engineering?

M: In high school, my success in STEM subjects led me to take an Architectural AutoCAD class at the Career and Technology Center in Frederick, MD. Thinking that I wanted to study architecture, I also participated in the ACE Mentor Program, which focused on orienting students with the fields of architecture, construction, and engineering. I realized later that architecture was not the correct fit since it was more art-rather than math- and science-based. Not knowing exactly what I wanted to do, I then transitioned to pursuing my degree in mechanical engineering, since it’s widely applicable to many fields (ie. aerospace engineering, civil engineering, etc.)

A: As a kid, I wanted to be an archaeologist. I later acknowledged my knack for analytical thinking, so I pursued engineering during my high school years, and later received a full scholarship to study engineering in college.

What would you say to persuade or encourage someone to study –or even pursue a career– in STEM?

M: STEM explains how things work, from something as simple as how water freezes to as complicated as a how a space shuttle can reach the moon. Engineering is problem solving and design. Both can be applied to any career you may see yourself doing, whether it be handling the foot traffic of hikers or directing water away from trails at a national park, or designing a robotic prosthetic to help those with a missing limb. Engineering is fun and challenging every day.

A: It pays well (laughs). As an engineer, you earn the skill set to transform your imagination into reality. Engineering teaches you how to better your concept and design through trial and error. It also alters your way of thinking by sharpening your analytical skills, making it easier to grasp any concept quicker. You become a problem solver and tackle important issues of the world. For instance, I once helped design a robot that could isolate and burn off cancer cells without harming healthy organs. With further research, it could have replaced chemotherapy.

Like Matt and Anjali, JEM Engineering proudly supports students and professionals in pursuit of careers in STEM!