Frequency band, polarization, feed interface, Tx. power capability, and operating gain standing wave, side lobe level,TX/RX Isolation- these five parameters form the basic inputs that a purchaser needs to confirm internally before starting the inquiry process for a 9.0m Earth Station Antenna. When any one of them is missing, a quotation engineer usually finds it difficult to lock down the configuration. The following sections examine these five dimensions one by one and explain the constraint that each parameter places on system selection.
1. Frequency Band Sets the Starting Point for the Entire Electrical Specification
The 9.0m Earth Station Antennas (SSA-900) support two operating bands, C-Band and Ku-Band, but the two differ structurally operating frequency starting point, gain level, and feed interface size. A configuration for one band usually cannot be mixed with the other.
The C-Band receive frequency range is 3.4–4.2 GHz, and its transmit frequency range is 5.85–6.725 GHz. The Ku-Band receive frequency range is 10.95–12.75 GHz, and its transmit frequency range is 13.75–14.5 GHz. This frequency difference directly affects the electrical gain that the antenna aperture can achieve. At mid-band, the C-Band receive gain is 49.9 dBi and its transmit gain is 53.5 dBi, while the Ku-Band receive gain is 59.4 dBi and its transmit gain is 60.8 dBi. At the same aperture, different bands correspond to different wavelengths and beam characteristics, and the gain level therefore differs as well.
For this reason, once the frequency band is confirmed, parameters such as gain level, feed type, and interface specification become clear and form the basis for later configuration. If band information is missing at the inquiry stage, the remaining configuration parameters are usually difficult to confirm.
2. Polarization Affects the Selection Path for the Feed Assembly
Once the band is clear, the next item to confirm is polarization, because it affects the physical structure of the feed assembly and the applicable standard for cross-polarization isolation.
The antenna supports both linear and circular polarization in C-Band, while it supports both linear and circular polarization in Ku-Band. A purchaser needs to make the corresponding choice based on the polarization configuration of the satellite being used.
3. Feed Interface Specification Directly Constrains On-Site Installation Compatibility
After polarization and band are confirmed, the feed interface specification is the third parameter that needs to be verified in advance, because it involves the physical compatibility of on-site equipment. If the wrong option is selected, additional modification costs may arise during installation.
The feed interfaces of the 9.0m Earth Station Antenna are allocated by band as follows. The C-Band receive end uses CPR-229G, and the transmit end uses CPR-137G. The Ku-Band transmit and receive ends both use WR-75. The CPR series is a circular waveguide flange interface, while the WR series is a rectangular waveguide interface. The two differ in physical dimensions and connection method, and they usually cannot be interchanged directly.
The feed insertion loss that accompanies the interface also deserves attention. The feed insertion loss given on the product page is 0.2/0.3, 0.2, and 0.2/0.4 dB. Insertion loss adds directly to the link budget and affects the calculation of usable gain. In addition, the isolation between the transmit link and the receive link is 85 dB. This figure indicates the level of transmit power leakage into the receive end.
When the interface model is provided at the inquiry stage, the supplier can confirm the feed assembly more directly.
4. Tx. Power Capability Locks Down the Amplifier Matching Plan
Once the feed interface specification is confirmed, Tx. power capability is the fourth parameter that must be clarified before inquiry. It directly affects the selection of the amplifier unit and is a key constraint on whether the system integration plan can be closed.
The Tx. power capability of the antenna is allocated by band: 5 kW in C-Band and 2 kW in Ku-Band. These two figures are the Tx. power capability values stated for the antenna. Following common industry practice, a purchaser needs to provide the planned amplifier model or target output power at the same time as the inquiry, so that the supplier can verify the power-carrying margin of the feed link.
If the amplifier selection is still under evaluation, the purchaser should at least provide the band information, so that the supplier can match the corresponding item between the 5 kW and 2 kW power capacity options and complete a preliminary match of the supporting plan.
5. Operating Gain and GT Value EIPR Determine the Feasibility Boundary of the Link Budget
The final key input is operating gain and G/T value, which is also the core electrical indicator for judging whether the system link budget is feasible.
The calculation of G/T value is affected by both gain and system noise temperature, and the antenna noise temperature varies with operating elevation. The noise temperature of the antenna in C-Band is as follows: 35°K at 10° elevation, 26°K at 30° elevation, and 24°K at 50° elevation. The corresponding noise temperatures in Ku-Band are 60°K, 50°K, and 48°K. The data on the product page shows that the lower the elevation, the higher the noise temperature.
In terms of typical G/T, when the elevation is above 10° in C-Band and a 30°LNA is used, the typical G/T value is 30.5 dB/K. Under the same elevation condition in Ku-Band with a 70°LNA, the typical G/T value is 37.3 dB/K. This means that the LNA selection and the actual operating elevation need to be provided together with the G/T value.
In addition, the antenna sidelobe performance follows the CCIR 580-4 standard. The -3dB beam width is 0.55° at the C-Band receive end and 0.4° at the transmit end, while it is 0.19° at the Ku-Band receive end and 0.16° at the transmit end. Beam width data is also listed in the product specification.
The specified VSWR is 1.25 for the listed C-Band and Ku-Band configurations.
Conclusion and Configuration Advice
The five parameters above - frequency band, polarization, feed interface, Tx. power capability, and operating gain with G/T value - are interrelated in technical logic and form a configuration confirmation chain. The frequency band determines the gain level, polarization defines the feed structure, the feed interface affects on-site installation compatibility, Tx. power capability constrains the upper limit of amplifier selection, and the G/T value relates to the link budget once elevation and LNA noise temperature are confirmed.
If you have any questions about your 9.0m Earth Station Antenna project during selection or inquiry, you are welcome to contact our team: info@satgroundapplication.com.
