JEM Engineering offers both on-site and remote RF testing services at our facility in Laurel, Maryland. Our Spherical Near-Field Chamber (SNF) and Tapered Antenna Testing Facility (TATF) can measure a number of antenna performance factors.
While many tests do not require the use of a test fixture, tests that involve a full 3-dimensional measurements in our TATF chamber will require some type of interfacing with our roll arm.
What materials are used for RF test fixtures?
Dielectric (non-conductive) materials, such as foam and wood, for example, are ideal for test fixturing. Such materials can support antennas and radomes without affecting their RF performance characteristics during a test.
Does JEM Engineering provide its own test fixtures?
We house a variety of simple test fixtures, which we use to test our own antennas, as well as our customers’. Our existing structures allow us to fixture multiple antennas during the allotted test time.
Customers may also provide their own test fixture(s).
What about custom fixtures?If the weight of the antenna under test is off-center by more than 36”, or if the antenna requires a more specific configuration, a custom fixture may be necessary.
We have the in-house capability to build custom fixtures. While customers are encouraged to provide their own fixturing specifications (for example, with drawings and dimensions), we are generally able to fabricate the appropriate fixtures based on a unit’s design and specific test requirements.
JEM Engineering offers all of our customers the added convenience of performing remote radiofrequency testing
We find that most of our customers prefer to visit our facilities for their scheduled radiofrequency tests. However, JEM also offers the option of remote testing, which may be preferable, depending on the specific requirements and circumstances.
The main purpose of our remote testing is to provide customers with the same quality rf tests without the need to travel (and the expenses associated with travel). Remote testing also comes at no extra cost. Our invoicing only takes into account our current rates and how much chamber time is spent on each test, no more, no less.
The process of scheduling a remote test is as simple as scheduling an onsite test and involves no additional paperwork.
1. Call or email us to begin the quoting process. Whenever a customer inquires after our in-house or remote radiofrequency testing services, we walk them through the same steps to determine how much chamber time is needed to complete the test. The customer fills out a form, which outlines the passive test requirements. Once we receive the form (which we commonly refer to as the “Test Plan”), we start generating the quote. Depending on the requirements, we can then determine whether or not the test is suitable for remote testing – and most tests are.
2. We schedule the test together. If a test date has not been specified prior to quoting, our team will consult with the customer to determine the best available date(s) to perform the test.
3. The customer ships the unit(s) and any additional equipment necessary to complete the test. The customer is responsible for any applicable fees associated with shipping and insurance.
4. Upon receipt of the components, we begin the test as scheduled. Throughout the testing process, our experts remain in communication with our customers to eliminate any confusion and ensure accurate results.
5. When the test is complete, we ship everything back, carefully packaged. We work with the recipient to send every component back via their preferred courier.
6. We invoice the customer. Our standard invoicing schedule is Net 10. Any deviation from this payment method will have been discussed prior to scheduling the test.
Our company takes pride in our flexibility when working with customers.
We understand that sometimes an onsite test becomes a remote test. In the event that travel is either inconvenient or no longer feasible, our technicians will perform the test(s) as scheduled, provided that we have received all the necessary components. If there is any delay on the sender’s part, we will also hold customer property for a specified amount of time, as outlined by our Terms and Conditions.*
In summation, almost any and every test performed onsite can be done completely remotely. As long as we have all the applicable components in-house, our experts can perform tests on even the largest units and with the most complex pieces of equipment.
* First-time customers receive a copy of our Terms & Conditions.
RF testing is used to measure a variety of different antenna attributes.
In this post, we discus a few ways in which rf 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.
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 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.
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.
The SNF chamber testing facility at JEM Engineering provides fast results to government and commercial groups looking to collect 4 pi steradian data. The electronically scanned probes take in readings from a full 360 degree measurement plane and can perform tests over frequencies from 400 MHz to 6 GHz. The SNF test chamber can analyze radiation patterns, efficiency, average gain and human body interaction of wireless system antennas for AMP, PCS, GSM, Bluetooth, IEEE 802.11, GPS and others.
SNF Custom Test Chamber
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. We will even build a custom fixture for you, if needed. The JEM 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. Testing times will depend on the number of frequency points measured, but tests of even over 100 Frequency Points can be completed from measurement to data results in about 10 minutes.
Analyses For SNF Chamber Testing
Results from the Spherical Near-Field Antenna Test can be presented in a variety of data formats, making them usable for future testing simulations. The data export is in ASCII text format which can be used in most standard software packages (such as Excel), and data can be exported according to customer requirements. This data can be modeled in 3D or 2D Radiation Patterns, Swept Gain and Efficiency plots, or used in simulations. Data packages typically consist of one or some of the following:
- Full spherical E-Phi and E-Theta values at each frequency
- Maximum Gain measured – Polarization, Phase and Amplitude
- Efficiency in dB and %
- Axial Ratio
- Individual Phi and Theta cuts
JEM Engineering is prepared to handle sight sensitive and classified samples. The SNF testing range is in a building that can be isolated for classified samples, if requested.
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 Spherical Near-Field 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 SNF Chamber at JEM.