Large Bandwidths in Small Packages: Spiral Antennas

Frequency independent antennas theoretically have no bandwidth limitations. Polarization, radiation pattern and impedance of such antennas remain unchanged over large bandwidth. Spiral antennas are a type of frequency independent antenna first introduced in the 1950s. Their spiral design allows them to be relatively small.

Characteristically, spiral antennas have low gain, but an array of spirals can produce higher gain. They transmit circularly polarized radio waves and receive linearly polarized waves in any orientation. They also attenuate circularly polarized signals received with the opposite-rotation. They can reject circularly polarized waves of one type, while being able to receive those with a different polarization.

Spiral Antennas | Archimedean Spiral vs Logarithmic Spiral

Spiral antennas usually have two conductive spiral arms, which extend from the center outwards. The direction of rotation of the spiral defines the direction of the antenna polarization. More spirals may be added to form a multi-spiral structure. Spiral antennas can take the form of a flat disc or a three-dimensional shape like a screw thread. As with microstrip antennas, the spiral can be printed or etched over a specifically chosen dielectric medium. While spiral antennas have several classifications, the Archimedean spiral and logarithmic spiral are the two most common.

Spiral antennas, such as several of those featured in JEM Engineering’s HSA product line, are widely used in the defense industry for sensing applications, where there is a need for very wideband antennas that can fit in smaller spaces. Spiral antenna arrays are used in military aircraft in the 1 to 18 GHz range. Other applications include direction-finding, frequency spectrum monitoring, as well as GPS, where RHCP antennas are common.

SNF Chamber Testing Capabilities

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.

Rapid Antenna Testing Services At JEM Engineering

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.

Rapid RF Testing Services

  • 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, within easy reach of both Baltimore and Washington DC, 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.

Custom Engineering Antenna Development

UHF Monocone AntennaFor quick turnaround custom antenna engineering with 100% satisfaction guarantee, partner with JEM Engineering. We offer custom antenna products, development, and testing services using our in-house rapid prototyping and testing facilities from 2 MHz to 40 GHz, including a tapered far-field anechoic chamber and a high-speed spherical near to far-field anechoic chamber.

Antenna Engineering

With expertise in quick-reaction custom antenna development, novel antenna products, and rapid RF testing services for both government and commercial applications, the engineers at JEM have decades of combined experience in the development and validation of antennas, microwave circuits, phased arrays and associated electronics.

Custom Antenna Development

JEM Engineering’s extensive antenna development experience allows us to design, build and validate custom antennas for a variety of applications. Some of the types of antennas we specialize in include:

  • Broadband Antennas – These antennas operate over a wide band of frequencies such as spirals, log-periodic dipoles and Vivaldi notch elements.
  • Narrowband Antennas – These antennas operate over narrow bandwidths, including patch and resonant cavity antennas.
  • Genetic Antennas – These antennas are designed by a computer based on an optimization algorithm, such as a genetic algorithm or some other iterative method.
  • Array Antenna & Beamformers – An array antenna consists of multiple radiating elements sometimes fed by a corporate power divider or beamformer.
  • Housings, Assemblies, and Structural Components – These are the mechanical components created to support electrical designs, and can range from simple enclosures, to protective covers, to mounting hardware, to moving mechanical structures.

The JEM Difference

JEM’s commitment to quality is instilled throughout every area of the company, from front-desk operations to prototyping, and we continue to grow our network of quality and compliance professionals.

Our transparent quality policy is met by:

  • Meeting our customers’ requirements and expectations;
  • Continually improving our product, striving to ship defect-free products;
  • Continually improving the effectiveness of our quality management system; and
  • Maintaining a motivated and highly skilled team.

Contact JEM Engineering For A Quote On Custom Antenna Development Services

See how JEM Engineering can bring your custom antenna needs to life. Contact us for a complimentary consultation and quote on custom antenna engineering services.

Woman-owned antenna engineering firm offers TATF and TAC chamber testing for government and commercial use

about-us-snfringJEM Engineering, LLC houses multiple RF test chambers at its facility in Laurel, Maryland, within easy reach of both Baltimore and Washington, District of Columbia. JEM has two anechoic test chambers, a spherical near-field chamber and a tapered antenna test chamber, which are used for both government and commercial applications. Customers testing at JEM have the advantage of working with knowledgeable and experienced RF technicians and engineers, who provide guidance and support to the testing experience and can assist with data analysis and interpretation.

Data files are available in a variety of easy-to-handle formats, and can be processed using software such as MATLAB, MathCAD or EXCEL. JEM can also generate a variety of useful reports and plots, including 3D radiation patterns for data collected using its Spherical Near-Field (SNF) Chamber. 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. ASCII data files are easily processed by third party analysis tools such as MATLAB, MathCAD or EXCEL.

RF antenna testing is only one of the services that JEM Engineering offers. The company, founded in 2001, also specializes in quick-reaction custom antenna design and development, and novel antenna products. JEM’s product offering includes, but is not limited to, radome antennas, vehicle mounted antennas, flight qualified antennas, monitoring antennas, outdoor antennas, concealed antannas, portable antennas, magnetic antennas, web antennas, communication antennas. JEM Engineering proudly holds ISO 9001:2015 certification.