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An Introduction to Antenna Testing

RF Testing: Measuring Effects on a Human Body

RF testing is used to measure a variety of different antenna attributes. In this post, we discus a few ways in which antenna testing can help determine if your device is performing the way it should.

Measuring Radiation Patterns – An antenna’s radiation pattern measures the strength of its radio waves in relation to the direction at which the waves travel. 3-Dimensional and/or 2-Dimensional renderings of the radiation pattern make it possible to visualize which direction(s) the antenna is radiating the strongest, as well as where it loses strength. Finding this pattern is fundamental in determining the antenna’s functionality.

Measuring Antenna Efficiency – The radiation efficiency, or simply “efficiency” of an antenna is commonly defined as the ratio of the power radiated from the antenna, in relation to the power delivered to the antenna. This measurement is typically measured in decibels (dB). It is important to determine that an antenna is performing at a certain level of efficiency before it used for its intended purpose. Significant discrepancies in efficiency may be the result of a manufacturing defect or design flaw.

Measuring Antenna Gain – An antenna’s gain is a measurement that combines the antenna’s efficiency with its directivity, which is essentially the antenna’s ability to receive energy better from a particular direction. It is beneficial to have higher gain when there is a predetermined direction that the antenna will be receiving a signal from. In contrast, lower gains are preferable when receiving signals from multiple unspecified directions. Therefore, measuring gain is important in qualifying an antenna, particularly for its direction-finding and/or signal-receiving abilities.

Realizing any Effects on the Human Body – It is important to make sure that the use of certain antennas, especially those that are to be worn on one’s person, will not have adverse effects on the human body. Some testing chambers, such as the SNF chamber at JEM Engineering’s facility in Laurel, are able to accommodate human test subjects.

At JEM, we understand that accurate measurement of antenna electrical performance is critical. Therefore we offer a range of rapid antenna testing services from 80 MHz to 40 GHz. Our TATF and SNF test chambers are able to deliver the aforementioned measurements within hours, as opposed to days. Our experts also specialize in analyzing the data, helping our clients improve and perfect their custom product designs. For more information, feel free to contact us.

Antenna 101: Types and Applications

Antenna 101: Types and Applications

We are experts in custom antenna design and manufacturing for various applications. Some common applications include vehicular, airborne, communications, SIGINT (signal intelligence), and ISR (intelligence, surveillance, and reconnaissance). While certain types of antennas are more suitable for each of these specific applications, many of our products are versatile and multi-platform.

In this article, we take a look at some of the different types of antennas, and what applications they can be used for.

Broadband Antennas – These antennas operate over a wide band of frequencies, or “bandwidths.”  Generally, the bandwidths over which they operate are higher than 1 octave. They come in a variety of forms, including spirals, log-periodic antennas, dipoles and Vivaldi notch elements.


An example of a broadband antenna, the HSA-056 is a 6″ spiral ideally suited for handheld and vehicular applications. With its wide bandwidth, broad beamwidth, and high RF efficiency, the antenna is also suitable for applications such as SIGINT, EW, and wideband communications.

Narrowband Antenna – In contrast to broadband antennas, narrowband antennas operate over relatively narrow bandwidths, generally much less than 1 octave. Patch and resonant cavity antennas are typical examples of narrowband antennas.


The RDF-8696 is a narrowband transducer for short range reading and writing of RFID tags including GEN2 tags. Some of the applications it can be used for include printers and various forms of automation equipment.

Antenna Arrays & Beamformers – Array antennas consist of multiple radiating elements. In some cases, these elements are fed by a corporate power divider or “beamformer.” The simplest beamformer is a power division network, which yields a fixed radiation beam. A beamformer that incorporates controllable phase or delay elements is called a steerable beam array or “phased array.”


Also nicknamed the “Hexband Array,” the MBA-0127 is compact, low-profile, single-port antenna covering multiple bands from 400MHz to 2.2GHz. This array is useful for multiband communications, airborne applications, ISR applications, and SIGINT.

Genetic AntennaThese antennas are designed entirely by an optimization algorithm, which can be a genetic algorithm or some other iterative method. While many antennas are pre-existent designs that are modified through optimizations, these antennas are entirely new designs generated solely via computer.

Genetic Antenna

Genetic antennas are perhaps the most unique, mainly because they are almost completely custom, like the one pictured above.

Introducing the HSA-218 Compact Spiral Antenna

HSA-218 Compact Spiral Antenna

Introducing the HSA-218 Compact Spiral Antenna

JEM Engineering is proud to announce the release of our newest addition to our vast product line: the HSA-218 Spiral Antenna (above).

Ideally suited for airborne and vehicular applications, this antenna delivers wide bandwidth, broad beamwidth, and high RF efficiency in a relatively small package.

Also, like many of our products, this compact spiral antenna is rugged and weather resistant.


Product Spotlight: The MultiBand Airborne ISR Antenna

JEM Engineering’s MBA product line consists of multi-band antennas that are suitable for airborne and ISR applications. These flight-qualified antennas are shock and vibration tested according to RTCA DO-160G standards.


One of our newest additions to the MBA product line, the MBA-0202 is an antenna array with two output ports. It has excellent low frequency performance and operates at frequencies between 650 to 1050 MHz, as well as 1500 to 2750 MHz. Additionally, with its 2-inch thickness, this array is mounted behind a pod, blister, or panel on an airborne platform.


Even with its comparatively simpler, box-like appearance, the MBA-0203 has all the functionality of the MBA-0202, plus a third output port and an additional frequency range of 3600 to 5900 MHz. The low-profile array is also 2 inches thick and mountable onto an aircraft.

If you would like to request additional information on these antennas, email us at Visit our Flight-Qualified Products Page to view our selection of broadband, conformal, high-power, and high-gain antennas. 



Why I Chose a Career in STEM

Two Company Leaders Share Why They Chose a Career in STEM

“STEM” stands for Science, Technology, Engineering, and Mathematics.  

In celebration of STEM Day (November 8) we asked our CEO, Nancy Lilly, and our Director of Antenna Development, Victor Sanchez, why they decided to pursue a career in STEM, and this is what they said…

Ever since I was a child, I have been curious about how things worked. I would tear apart old telephones, computers, toasters…and my questions were always, “Why did they build it that way?” and “What do these components do?” I would find books to research electrical components.

When I was about 12 years old, I would accompany my father to do electrical wiring installations. He started teaching me how to read electrical diagrams. My curiosity grew to a point where I knew I wanted to be an engineer.

At first, I wasn’t sure what kind of engineer, until I found that I also enjoyed the process of building things. I also wanted the opportunity to be around people and solve problems. I realized later that I wanted to be a manufacturing engineer.

Nancy Lilly, Chief Executive Officer and President of JEM Engineering



Nancy Lilly

President & CEO

“I never made a conscious decision to choose a STEM-related career; it just flowed naturally as a result of my interests. As a kid, math and science were my favorite subjects and my heroes always seemed to be involved in them (Apollo Astronauts, Mr. Spock on Star Trek, and even my older sister who was studying computer engineering).

In middle and high school, I was lucky to have some great teachers whose enthusiasm helped further my pursuits. Around this time, computers became more accessible and I can recall spending many weekend hours in my local Radio Shack store writing computer programs on the display floor computer (a TRS-80). There was no compelling reason for this; I was just naturally interested because I found it amazing and fun. These days, as an electrical engineer by profession, I still find this to be true and generally find myself enthusiastic about the work I do every day.”

Victor Sanchez, Director of Antenna Development for JEM Engineering



Victor Sanchez

Director of Antenna Development


JEM Engineering proudly supports students and professionals in pursuit of careers in STEM, for our company is built on the passions of such individuals.

More About Nancy

Nancy Lilly has significant RF experience working in a variety of engineering capacities. Before launching JEM Engineering in 2001, Nancy was a manufacturing engineer for both Wang and Scope Laboratories of Northern VA. She has more than 10 years of experience in antenna and RF applications and system design. She also has experience in quality engineering. Previously, she was quality assurance manager for Racal Avionics of Silver Spring, MD and a quality engineer for Arbitron of Columbia, MD. Nancy was an examiner for the 2004 U.S. Senate Productivity & Maryland Quality Awards for The University of Maryland Center for Quality & Productivity. Nancy holds a BS in both chemistry and industrial engineering from the University of Puerto Rico and Polytechnic University, respectively. She also holds a master’s degree in Engineering Administration from George Washington University.

As Chief Executive Officer and President of JEM, Nancy has received numerous awards, including the National Association of Professional and Executive Women’s “Woman of the Year Award” for her contributions to antenna design and manufacturing.  In 2006, Nancy was selected among Maryland’s Top 100 Minority Business Enterprise Awardees.”


More About Victor

Victor Sanchez has over 25 years of experience working in the field of RF / Antenna Engineering. He has a proven record of successful antenna development, technical innovation and program management. His roles have ranged from Research & Development to Integration & Test for breadboard and production antennas ranging from single elements at UHF to Ka-band phased arrays. He has conducted this work in both small and large team environments at Atlantic Aerospace Electronics Corporation, L-3 Communications and Northrop Grumman Corporation. While at Northrop Grumman, he earned an “Innovation of the Year Award” for his Broadband Additively Manufactured Array Antenna. He is currently Director of Antenna Engineering at JEM Engineering, where his principal responsibilities involve acquisition and technical execution of both government funded R&D and commercial antenna projects.

Victor holds BSEE and MSEE degrees in Electrical Engineering from the University of Massachusetts. He is a senior member of the Institute of Electrical Electronic Engineers (IEEE) and has numerous technical publications and patents, including the Monolithic Phased Array Antenna System.

The Makings of A Reliable Antenna

Every product, specialty or off-the-shelf, must be designed, tested, and perfected by a team of experts, so that the end-user can be assured of its reliability.

An antenna is no exception.

Our customers trust us to provide them with custom products, many of which have never been made in the past –or even conceptualized.

In this post, we share some of our antenna designing know-how…

1. Knowing where to start. Every single one of our antennas started out as a concept. Either a client or one of our own engineers wanted a device that could deliver a specific result, and our team worked to bring that concept to full-scale production. Our experts find out what the client is looking for, and quickly figure out how to make it happen. Our engineers have several decades of combined experience creating detailed drawings from 2-dimensional drafts to 3-dimensional CAD models.

Mechanical Design: 2-Dimensional Rendering
2-Dimensional Rendering of Antenna

2. Performing a structural analysis. Naturally, one would want to make sure that the design doesn’t just look good on paper, but it also holds together, at the very least. However, it would be preferable to detect design flaws before spending money on building materials. For instance, COSMOS Static Analysis is an cost-effective way to perform a structural analysis on a computer-generated model, such as a SolidModel. We use this method to assess the feasibility of custom design projects.

COSMOS Static Analysis on a SolidModel
COSMOS Static Analysis on a SolidModel (Animation may not play on certain devices)

3. Developing a prototype. Before one builds the final product, they must create a prototype to not only further evaluate a design, but to also establish the most efficient assembly methods for it, and assess the cost effectiveness of its bill of materials. This also leads us to the next item on the list…

Mechanical Design: Close-Up of Antenna's Collapsible Components
Close-Up of Antenna’s Collapsible Components

4. Using the right materials. The difference between selecting one material over another can not only mean cost savings, but also overall better performance and longevity. Our mechanical engineers excel at finding the best materials for a project, measurably increasing the practicality of a product.

Mechanical Design: Close-Up of Antenna's Various Materials
Close-Up of Antenna’s Various Materials

5. Seeing the prototype in action. So now it’s time to test the prototype. Before the product can go out into the field, it has to perform well in the lab. In our case, the antenna has to be carefully tested in one of our two test chambers by a well-trained and highly-skilled technician, who will provide guidance and support during the test, as well as assist with data analysis and interpretation. In a previous post, we explore antenna qualification in more detail. Read it here.

Mechanical Design: The Antenna, Awaiting Testing in Our SNF Chamber
The Antenna, Awaiting Testing in Our SNF Chamber
6. Thinking about the whole package. After it is determined that the product works, the next point of consideration is its durability. Apart from material selection (see No. 4), the mechanical engineer designs the product’s housing and internal components so that as a unit it can resist various environmental conditions. To make sure that the final product will survive, it must be put through rigorous environmental testing, including shock, vibration, heat, moisture, chemicals, wind, and frost. This is especially important for devices used primarily outdoors and/or mounted on moving objects. Our external testing partners have these specific testing capabilities, which become available to our clients through us. Additionally, we can perform engineering analyses for electronics packaging to ensure that the encased antenna and its components are stored correctly.

Mechanical Design: Finished Antenna Product


In summary, designing a functional and structurally sound antenna has many crucial and complicated processes. Luckily, we can help you every step of the way! JEM Engineering staffs a Mechanical Engineering department capable of providing expertise to every product design. Send us an inquiry or call us at 301.317.1070 to let us know what you need!


Quality & Customer Service – Our Policy 

JEM Engineering exceeds customer expectations by providing custom antenna design, manufacturing and testing solutions with a commitment to comply with customer requirements and continually improve the effectiveness of the quality management system by maintaining a motivated, highly skilled and innovative team, and becoming a leader in our industry. Our commitment to quality is evident as our Quality Management System (QMS) is ISO 9001 Certified.


September 20, 2017: JEM Engineering Celebrates 15 Years of Service

Celebrating 15 Years of Service
Since our incorporation on September 20, 2002, JEM Engineering, LLC has developed, supplied, and tested antennas and various RF technologies for both commercial and government applications.

Our products and services have been used in programs set forth by the United States Department of Defense, as well as by many of its contractors throughout the past fifteen years.

We will continue to do our part in helping the US Armed Forces ensure the safety of this Nation.

JEM Partners with the American Red Cross to support disaster relief

JEM Engineering, through the American Red Cross, will be providing financial assistance to households that were severely impacted by recent Hurricanes Harvey and Irma, as well as the impending Hurricane Jose.

As part of our efforts, we are also collecting monetary donations from the community. If you are interested in donating, you may contact us for additional information.

Why donate through JEM? Make your donations go twice as far!

Every gift you make is significant in our disaster relief efforts. We want to double your gifts so that our efforts will move twice as fast! JEM will match donations you make by 100%.


       Disaster Relief: American Red Cross

Are your antennas up to the test?

JEM Engineering's SNF Chamber in Laurel, MD

Like with most products, an antenna’s outstanding performance in the field must be preceded by outstanding performance in the lab.

It is JEM Engineering’s job to not only design and manufacture antenna products, but also to qualify them to meet RF specifications, as well as environmental standards such as military standard MIL-STD-810 and RTCA/DO-160. Because of this, not only do our products survive strenuous environmental conditions; they perform well. We extend the same guarantee to our customers by offering them the same qualification services.

Our rigorous qualification procedures combine our own internal testing capabilities with those of our external testing partners. In this post, we list some of our in-house qualification capabilities.

• Efficiency Measurements

The radiation efficiency, or simply “efficiency” of an antenna is commonly defined as the ratio of the power radiated from the antenna, in relation to the power delivered to the antenna. JEM’s Spherical Near-field Chamber (SNF) and Tapered Antenna Test Facility (TATF) chambers generate efficiency plots, in addition to as addition to radiation patterns, and ASCII Data Files.

• Directivity Measurements 

Directivity is one on of an antenna’s key performance factors. One can define it as the ability of an antenna to focus energy in a particular direction when transmitting. Directivity also measures the antenna’s ability to receive energy better from a particular direction.

• Gain Measurements

Another useful performance measurement is the antenna’s gain. It combines the antenna’s efficiency with its directivity. The gain measurements we provide as part of our data package include peak, average, maximum linear, minimum linear, horizontal, and vertical, as applicable. Additionally, SNF and TATF chambers generate gain measurements for antennas within two different frequency ranges. The SNF measures from 400 MHz to 6 GHz , while the TATF measures 80 MHz to 40 GHz.

VSWR and Return Loss

Voltage standing wave ratio, or “VSWR,” is a measure that describes how well the antenna impedance -or voltage to the current at the antenna’s input- “matches” to the radio or transmission line it is connected to. A good match allows a transmitter or receiver to deliver power to an antenna without excessive reflection back on the line (return loss). At JEM, a single VSWR measurment, including system calibration, takes less than 10 minutes. In fact, minus calibration, it only takes 1 minute or less to complete a test!

• Radiation Patterns

An antenna’s radiation pattern measures the strength of its radio waves in relation to the direction at which the waves travel. We can generate both 3-Dimensional, as well as 2-Dimensional renderings of radiation patterns.

Steered Array 3-D Plot GIF
Steered Array 2-D Plot
Steered Array 3-D Pot
 Steered Array 2-D Plot

• Human Body Interaction

Besides producing full-spherical radiation patterns, our SNF chamber can accommodate a human test subject. This allows us to take accurate measurements of body interaction effects on body worn and handheld devices.

Qualification Capabilities - Testing Human Interaction Effects on Body-Worn Antenna

JEM Engineering technicians testing a wearable antenna in our SNF chamber in Laurel, MD

• Temperature Effects

Temperature testing allows us to determine how a complete product,  its parts, and its sub-assemblies are affected by extreme temperatures, as well as changes in temperatures. Consequently, this also allows us to assist customers in analyzing the cost effectiveness of manufacturing a product and using its components.

• Simulations

Our team of experts has access to advanced simulation software, therefore, allowing us to measure in-situ performance, and eliminating need to run a physical test.

Our Communications Antennas

At JEM we offer a variety of communications antennas, each tailored to meet a specific need. In this article, we reintroduce some of our comms antennas.

Handheld Communications Antennas – Our high-power antennas are ground plane independent. The ruggedized, weather-resistant JEM‐9051 is just one of the handheld communication antennas we designed. Nicknamed “The Power Ducky”, it is a flexible whip antenna covering 90 – 512 MHz with 25 W CW of power handling. This antenna is designed for low‐profile and man‐portable wideband communications using high power amplifiers.

JEM-9051 | Frequency Band:  90 – 512 MHz | VSWR: 1 (typical) | Polarization: Vertical, Linear | Gain:  ‐20 dBi to 0 dBi  | Power: 25 Watts CW

Communications Antennas: JEM-9051


+ High Power Handheld Antenna

+ Ground Plane Independent

+ Class Leading Gain & Pattern

Request More Info Download Spec Sheet


QHA-081| Frequency Band: 800-1000 MHz | VSWR: <2.0:1 | Polarization: Circular, RHCP | Gain: >8dBi | Power: 25 Watts CWIn-building Communications Antennas  – One of our antenna products’ common features is versatility. The QHA-081 right-hand Helix Antenna is circularly polarized, operating at frequencies 800-1000 MHz. Aside from in-building communications, this antenna is suitable for multiple wireless applications.

Communications Antennas: QHA-081


+ Circularly Polarized

+ Designed for in-building communications

+ Suitable for Multiple Wireless Applications

Request More Info Download Spec Sheet




Unmanned Aerial Vehicle (UAV) Communications Antennas – Another versatile antenna is the UVW-1547, a UAV and vehicular qualified antenna is designed for ground-to-ground, ground-to-air, and air-to-ground communications systems. This antenna is optimized for the L, S, and C-band downlinks with low drag operations. The antenna is also optimal for SIGINT and sensor systems.

UVW-1547 | Frequency Band:  1500 – 4700 MHz | VSWR: < 3.0 : 1 | Polarization: Vertical, Linear | Gain:  0 dBi (Boresight) 3.3 – 9 dBi (+20°) | Power: 10 Watts CW

Communications Antennas: UVW-1547

Designed for Ground‐to-Ground,Ground‐to‐Air, and Air‐to‐Ground Communications Systems

+ Suitable for SIGINT, ISR, and Sensor Systems

+ Optional magnetic mount or tubular chassis mounting assembly

Request More Info Download Spec Sheet



Satellite (SATCOM) Communications Antennas – We have developed a number of antennas used for satellite communications, many of which can also be mounted onto a vehicle’s or an aircraft’s surface with no degradation to the pattern or VSWR. The HSA‐2438LP, also known as the “Low-Profule MUOS SATCOM Antenna” is a hybrid spiral antenna operates on 240 – 380 MHz. It can be flush mounted on a vehicle or airborne surface and its pattern is designed for uniform gain overhead to 40 degrees in elevation.

HSA-2438LP | Frequency Band:  240 – 380 MHz | VSWR: < 1.5 : 1 | Polarization: Vertical, Linear | Gain:  3 dBic, overhead   | Power: 50 Watts CW

Communications Antennas: HSA-2438LP


Flush mountable for low visibility

+ Ground Plane Independent

+ Optional Clamp Mounts for Quick Connect in All-Terrain Vehicle Operation

Request More Info Download Spec Sheet

More about JEM Engineering

JEM Engineering’s team boasts over 150 years of combined experience, allowing them to take an antenna concept all the way through to full-scale production. All JEM’s antennas are qualified and tested in-house at their facility in Laurel, MD.