Antenna¶
Asset reference
Concept¶
An antenna is the RF aperture and radiation pattern on a spacecraft, facility, or vehicle. Link Complex transmitters and receivers read directional gain from a linked antenna on the same parent. Simple RF uses a fixed EIRP / G/T and does not need this asset.
Boresight is +Z. Mounting and pointing are the same model as sensors — Mounted assets. Changing the pattern does not by itself re-run Link; apply the antenna, then re-run the analysis.
When to use¶
| Use an antenna when… | You can omit it when… |
|---|---|
| Complex TX/RX budgets need gain vs off-boresight angle | Simple RF (implicit isotropic EIRP / G/T) |
| You want the 3D pattern lobe in Design | Geometry-only Link (no budget) |
Generic¶
| Parameter | Type | Default / options |
|---|---|---|
| Name | text | — |
| Active | checkbox | — |
| Parent asset | select | spacecraft, facility, vehicle |
| Role | select | tx / rx / txrx (default txrx) |
| Color | color | #FF8C00 |
| Mesh phi | integer ≥ 8 | 144 |
| Mesh theta | integer ≥ 8 | 72 |
Role is which chain may link this aperture (transmit, receive, or both). Mesh phi / theta is only the 3D lobe tessellation — denser mesh looks smoother and costs more to draw; it does not change the analytic gain used in Link.
Antenna Properties — parent, role, color, mesh density.
Radiation patterns¶
Pattern model picks a catalogue entry. The fields below the dropdown then change. Switching model resets those parameters to that model’s defaults.
Define Using (aperture models)¶
Gaussian, Cosine Aperture, and Parabolic share a Define Using control:
| Mode | You set | The editor derives |
|---|---|---|
| beamwidth | 3 dB beamwidth | Diameter and peak gain |
| diameter | Physical diameter | Beamwidth and peak gain |
| gain | Peak gain [dBi] | Diameter and beamwidth |
Parabolic defaults to diameter. Frequency and aperture efficiency still apply in every mode. Backlobe gain floors the pattern behind the aperture.
Ideal and elementary¶
| Pattern (editor) | Use when… | Extra knobs |
|---|---|---|
| Isotropic | Constant gain in every direction (default; closest to Simple RF) | Frequency, aperture efficiency, Gain [dBi] (default 0) |
| Dipole | Short / half-wave element, not a dish | Length / wavelength (default 0.5), backlobe, Gain default 2.15 dBi |
Aperture and shaped beams¶
| Pattern (editor) | Use when… | Extra knobs |
|---|---|---|
| Gaussian | Smooth pencil beam, no explicit side-lobe structure | Define Using + backlobe |
| Cosine Aperture | Circular aperture with a cosⁿ taper | Define Using; optional exponent n |
| Parabolic | Reflector / dish sized by diameter or HPBW | Define Using; main-lobe half-angle |
| Rectangular Gaussian | Elliptical beam (different az / el widths) | Azimuth and elevation 3 dB beamwidths |
| Horn Rectangular | Pyramid / sectoral horn | HPBW in E-plane and H-plane |
| Patch Simple (microstrip) | Low-gain patch (typical ~6 dBi, 2.4 GHz default) | E- / H-plane HPBW |
| Array Factor (phased grid) | Regular planar array, including steered beams | Elements in X/Y, spacing in λ, steer θ / φ |
| Side-Lobe Template | Hand-placed first (and optional second) side lobes | Main HPBW, lobe levels / offsets / width |
ITU-R reference patterns¶
These are recommendation envelopes (FSS / BSS / DTH coordination and design objectives), not a measured pattern of a named commercial dish. Use them when the study should follow a published mask rather than a Gaussian fit.
| Pattern (editor) | Typical story |
|---|---|
| ITU-R S.672 (FSS earth station) | FSS ES reference |
| ITU-R S.1528 (FSS reference) | FSS reference (higher-band default) |
| ITU-R BO.1213 (DTH receive) | Direct-to-home receive |
| ITU-R S.465/S.580 cosⁿ | Cosine-power main lobe in that family |
| ITU-R S.465 (FSS coordination envelope) | Coordination envelope (32 − 25 log φ); optional diameter and Appendix 8 main lobe |
| ITU-R S.580 (GSO side-lobe objective) | GSO ES side-lobe design objective (29 − 25 log φ) |
| ITU-R S.731 (Ku-band tri-segment) | Ku-band three-segment ES envelope |
| ITU-R F.699 (1st side-lobe plateau) | First side-lobe plateau (F.699-6 style) |
| ITU-R BO.1445 (BSS sat fast roll-off) | BSS satellite fast roll-off |
| ITU Appendix 8 + 3 side-lobes | Appendix 8 main lobe plus up to three explicit side lobes |
Most ITU rows share design frequency, efficiency, main-lobe gain, backlobe, and 3 dB beamwidth. Envelope rows may add Diameter and Appendix 8 main lobe.
Imported grid¶
Imported Grid (CSV/NPZ) loads a measured or external θ/φ gain table (Pattern file, gain in dB or linear). Use this when the catalogue shapes are not enough.
Antenna — Pattern model and the dynamic fields for the selected pattern.
Pointing¶
See Mounted assets (offsets, Euler sequence, Body-Fixed / Scanning / Conical Spin / Targeted). Off-boresight angle in Complex Link is this pointing plus the pattern above.
Plan limits¶
antennaPerParent at creation.