RFPlanar vs. Conformal Antennas: Key Differences Explained
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This article highlights the differences between planar and conformal antennas. Let’s dive into the specifications:
| Specification | Planar Antenna | Conformal Antenna |
|---|---|---|
| Technology | Mature | Not matured yet |
| Beam Control | Phase only sufficient | Amplitude and phase more complicated |
| Polarisation | Single can be used; dual often desired | Polarisation control required, especially if doubly curved |
| Gain | Drops with increased scan | Controlled, depends on shape |
| Frequency Bandwidth | Typically 20% | Wider planar antenna is possible |
| Angular Coverage | Limited to roughly +/-60 degrees | Very wide, half sphere |
| Radar Cross Section (RCS) | Large RCS | Lower than planer |
| Installation on Platform | Planer shapes limits due to swept volume | Structurally integrated, leave extra space, no drag |
| Radome | Aberration effects | No conventional radome, no bore sight error |
| Packaging of Electronics | Known multilayer solutions | Size restriction if large curvature, facets possible |
Understanding the Differences
Let’s break down what these differences mean in practical terms:
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Technology Maturity: Planar antennas are a more established technology. Conformal antennas are still evolving, meaning there are ongoing developments and refinements in their design and implementation.
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Beam Control: Steering the radio beam of a planar antenna is typically achieved by adjusting the phase of the signals. Conformal antennas require more complex control of both the amplitude and phase to effectively shape and steer the beam, especially when dealing with complex curvatures.
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Polarization: Planar antennas can be designed for single or dual polarization. Conformal antennas require careful polarization control, particularly when they are curved in two dimensions.
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Gain and Scan: The gain of a planar antenna tends to decrease as the beam is steered further away from the antenna’s normal direction (scan). Conformal antennas offer more control over gain, as it’s dependent on the antenna’s specific shape and curvature.
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Bandwidth: Planar antennas usually offer a bandwidth of around 20% of their center frequency. Conformal antennas can achieve wider bandwidths, although this isn’t always guaranteed.
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Angular Coverage: Planar antennas generally provide a limited coverage angle, typically around +/-60 degrees. Conformal antennas excel in offering very wide angular coverage, potentially covering a hemisphere.
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Radar Cross Section (RCS): A planar antenna generally has a larger radar cross-section, meaning it is more easily detected by radar. Conformal antennas, due to their shape and integration into surfaces, often present a lower RCS, making them harder to detect.
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Installation: Planar antennas, being flat, can be limited by the space they take up. Conformal antennas are structurally integrated, minimizing drag and fitting smoothly into curved surfaces, though this requires careful design and may require extra space.
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Radome Effects: Planar antennas that use a radome (a protective cover) can suffer from aberrations that affect beam accuracy. Conformal antennas typically don’t use conventional radomes, eliminating these issues.
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Packaging: Planar antennas benefit from well-established multilayer electronics packaging techniques. Conformal antennas face packaging challenges, especially when dealing with significant curvature, requiring faceted designs in some cases.
