Adjustment of Satellite Communication Antenna Polarization Angle

Adjustment of Satellite Communication Antenna Polarization Angle: Linear Polarization and Circular Polarization
How to Adjust Horizontal/Vertical Polarization Angles
Adjustment Method for Linear-Polarization Signals: Ground Fixed Stations and SOTM Terminals
For linear-polarized signals, technicians typically adjust the polarization angle after completing azimuth and elevation alignment. Once the antenna is accurately pointed, the polarization adjustment can begin.
First, based on the satellite’s orbital position and the geographic coordinates of the ground antenna, the azimuth, elevation, and polarization angle are calculated. After obtaining the required polarization angle, the technician rotates the antenna feed—most commonly by rotating the LNB or the feed assembly—to ensure that the antenna’s receive/transmit polarization is properly aligned with the satellite’s incoming signal.
This rotation aligns the ground antenna’s horizontal or vertical polarization with the satellite’s polarization orientation, minimizing cross-polarization interference and maximizing link performance.
If the LNB bracket includes a polarization scale, the technician can simply rotate the LNB to the calculated theoretical polarization angle indicated on the scale.
In addition, many modern fixed ground stations and SOTM antennas use automatic satellite acquisition. The antenna control unit (ACU) drives a motor to automatically rotate the feed (LNB) to the required theoretical polarization angle.
There is also a manual polarization adjustment method for rotating the antenna feed (LNB). For example:
Suppose a satellite transmits a horizontal-polarization signal at 12250.2 MHz and a vertical-polarization signal at 12250 MHz, and the ground antenna needs to align to the horizontal-polarization signal.
Horizontal and vertical polarizations are orthogonal to each other in space.
A well-designed antenna optimized for horizontal polarization has extremely low sensitivity to the vertical-polarized wave. When the antenna is perfectly aligned to horizontal polarization, its response to the vertical-polarized signal is theoretically zero.
Therefore, the goal of polarization adjustment is to:
Maximize the received power of the desired signal (12250.2 MHz, horizontal polarization).
Minimize the power of the undesired orthogonal signal (12250 MHz, vertical polarization)—ideally making it disappear on the spectrum analyzer.
When these conditions are met, the antenna is perfectly aligned with the horizontal-polarization signal while achieving maximum suppression of the orthogonal vertical-polarization signal.
Manual Polarization Adjustment Procedure for Ground Station Antennas：

· Preparation and Calculation: Input the local location and satellite longitude, and calculate the theoretical polarization angle.
· Equipment Connection and Setup: Properly connect the spectrum analyzer to the LNB output, and configure it to clearly observe the target signal as well as potential interference signals.
· Azimuth and Elevation Adjustment: Adjust the antenna’s azimuth and elevation angles so that the antenna points toward the satellite.
· Polarization Angle Adjustment: Rotate the antenna feed (LNB) to the theoretical polarization angle to initially acquire the signal.
· Fine-Tuning Optimization (Core Loop): This is a precise and iterative process. By slightly rotating the LNB and monitoring the spectrum analyzer in real time, maximize the target signal power while minimizing the interference signal power to find the optimal peak point.
During manual polarization adjustment, continuously monitor the power of the horizontally polarized signal (desired signal) and the orthogonal vertically polarized signal (interference), and calculate the cross-polarization discrimination (XPD).

How is the antenna polarization angle adjusted for circularly polarized signals?
In fact, circularly polarized antennas do not require polarization angle adjustment; only the polarization state needs to be selected. Taking a Ka-band circularly polarized satellite communication portable station as an example:
The antenna of the portable station has only two polarization states: 0° and 180°. The feed (OMT or waveguide switch) is designed to switch between RHCP (right-hand circular polarization) and LHCP (left-hand circular polarization) operation modes. This is a simple two-option configuration rather than a finely adjustable angle.
During satellite acquisition, the user simply switches the feed between 0° and 180° manually; the antenna’s polarization does not require motorized servo adjustment. It is important to note that if the circular polarization sense is incorrect (for example, using an LHCP antenna to receive an RHCP signal), signal loss can reach 25–30 dB, causing the communication link to fail completely. During commissioning, only one of the two states (0° or 180°) can establish a valid connection, while the other will result in almost no signal.

📡 Why is the Antesky Flyaway Antenna Easier to Align Polarization in Engineering Applications?
Antesky 1.0-2.4 Meter Flyaway antenna is engineered with practical field deployment requirements in mind, making polarization alignment significantly more efficient:
• Precise Feed Polarization Scale
Antesky 1.0-2.4 Meter Flyaway antenna: The linear-polarized feed is equipped with a ±90° mechanical scale, perfectly matching the engineering workflow described in this article—allowing technicians to “coarsely set the polarization angle according to the theoretical value.”

• Optional Motorized Polarization Adjustment (for Fixed or Transportable Stations)
For users who need quicker setup, remote operation, or reliable repeatability (such as government, broadcast, emergency communications, or fixed ground stations), Antesky antenna can be configured with:
A polarization adjustment motor
Controller-based automatic positioning to the specified polarization angle

• 0°/180° Quick-Switch Circular Polarization Feed
For circular-polarized configurations, the antenna uses a feed design that supports instant switching between RHCP and LHCP.

• High Cross-Polarization Isolation
The feed system is optimized to provide excellent cross-polarization isolation, ensuring strong co-pol performance while suppressing unwanted cross-pol signals—matching the XPD requirements outlined earlier in the article.

Conclusion
This article systematically elaborates on the theoretical foundations and practical methods for adjusting the polarization angle of satellite communication antennas. By analyzing the characteristics of linear and circular polarization in different application scenarios, we recognize the critical impact of polarization alignment on communication quality. Linear polarization systems require precise polarization angle adjustment to ensure maximum signal reception and interference suppression, whereas circular polarization systems simplify the installation process through rotational direction matching.