RF MISO | Antenna selection guide
A lens antenna uses a lens to control the phase distribution of an electromagnetic wave. In a lens horn antenna, the horn illuminates a dielectric lens that shapes the outgoing beam. The practical benefit is not simply higher gain: a lens can help form a directional beam or concentrate energy at a specified working distance.
For RF engineers and procurement teams, the first question is: Does the application require a far-field beam or a finite focal spot? This guide explains the difference, the specifications that matter, and two RF MISO products that illustrate different selection requirements.
Browse RF MISO lens horn antenna models
Compare operating bands, interfaces and model-specific datasheets.
How Does a Lens Antenna Work?
A feed horn produces a wavefront whose phase varies across the illuminated region. A dielectric lens introduces a spatially varying phase delay through its shape, material properties, or both. For a collimating arrangement, the lens compensates for path-length differences so the emerging wavefront is approximately planar. A real, finite aperture still produces diffraction and a beam with nonzero angular width.
The feed position matters. Its effective phase center should be compatible with the lens design; the phase center is not necessarily at the horn aperture. Feed illumination, alignment and spacing influence the resulting pattern. University research on horn-lens systems describes this relationship and its role in achieving a uniform outgoing phase front. [1]
RF lenses are not limited to optical glass. Microwave designs can use low-loss dielectric materials such as PTFE or polyethylene; the appropriate material depends on frequency, loss and mechanical requirements. A passive lens does not amplify RF power. Any gain improvement comes from radiation distribution and efficiency, with material and reflection losses still present.
Collimation vs. Spot Focusing
RF MISO RM-SFLHA90-25 spot-focusing lens horn antenna. Real focal spots have finite size; the working-distance reference must be defined for the selected antenna.
A directional beam
When the requirement is directional transmission or antenna measurement, evaluate gain versus frequency, E- and H-plane beamwidths, sidelobes and cross-polarization. A narrow beam also makes pointing and fixture alignment more important. Do not assume that a high-gain lens horn provides a specified near-field focal distance.
A localized measurement region
A spot-focusing lens horn concentrates illumination around a target plane at a finite distance. This is useful in suitable free-space material-characterization arrangements, where sample size and illumination geometry affect the measurement. Research on focused microwave material measurements shows why focal-plane field characteristics matter alongside spot size. [2]
Specify the required distance and how it is measured, the operating frequency, sample dimensions and acceptable illuminated area. Ask whether the spot diameter is defined at a 3 dB level, 10 dB level, first null, or another criterion. Numbers using different definitions are not directly comparable.
Two RF MISO Lens Horn Antenna Examples
The following specifications come from the linked model-specific RF MISO datasheets. These are different operating bands and configurations, not interchangeable antennas.
| Specification | RM-LHA28-30 | RM-SFLHA90-25 |
|---|---|---|
| Antenna type | Lens horn | Spot-focusing lens horn |
| Frequency range | 38–40 GHz | 8.2–12.4 GHz |
| Key published value | 30 dBi typical gain | 300 mm focal length; 55 mm spot size* |
| VSWR | 1.3:1 typical | 1.5:1 maximum |
| Polarization | Linear | Linear |
| Interface | WR28 rectangular waveguide | SMA Female; WR90 waveguide section |
| Official datasheet | RM-LHA28-30 PDF | RM-SFLHA90-25 PDF |
*Focal length and spot size are listed in the datasheet’s Typical column. Its table does not identify a spot-size threshold or reference frequency. Confirm these conditions and the distance reference with RF MISO before defining a sample fixture. No gain value is inferred from the RM-SFLHA90-25 model suffix.
What to Check Before Selecting a Manufacturer
- Application and operating band. State whether you need a directional link, antenna measurement or localized sample illumination. Use the exact product band, not the full nominal range associated with a waveguide designation.
- Performance definitions. Separate typical values from guaranteed limits. Low VSWR alone does not establish gain, beam quality or measurement accuracy.
- Evidence behind the plots. Ask which data are simulated and which are measured. The linked RF MISO datasheets label their plot sections as simulation data; these should not be presented as individual-unit test reports.
- Mechanical and RF integration. Check the external connector or flange, mounting drawing, available travel and alignment tolerance. Include adapter and cable losses in the system budget.
- Project conditions. Specify power, environment and quantity. A lens face is not, by itself, evidence of a weatherproof enclosure or a particular environmental rating.
Lens integration involves trade-offs: phase correction and beam shaping can be valuable, but lens losses, aperture size, weight, alignment and cost still need review. Neither a lens horn nor a reflector is universally the better choice; the decision should follow the field distribution and mechanical envelope your application requires.
Work with RF MISO on Model Selection
RF MISO is an antenna manufacturer and supplier based in Chengdu, China. Our R&D and antenna testing pages introduce the company’s engineering activities. For a lens antenna inquiry, send your frequency band, polarization, gain or focusing objective, interface and installation constraints so the team can review the appropriate model and documentation.
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For specifications and quotation inquiries: info@rf-miso.com | Contact RF MISO
Frequently Asked Questions
Does a lens antenna always produce a narrow beam?
No. Beamwidth depends on aperture, frequency, feed illumination and lens design. A broadband model should be evaluated across the required band, not by one headline gain figure.
Can a standard lens horn replace a spot-focusing antenna?
Not without verification. A specified gain does not guarantee the required focal distance, spot diameter or field distribution at a nearby sample plane.
What should an RFQ include?
Include the operating band, application, polarization, gain or spot-size requirement, working distance, RF interface, mounting constraints and quantity. Identify which performance values must be guaranteed.
Post time: Sep-14-2026
