Universal land mobile antenna for mobile broadband communication via Ka satellites
Land mobile antenna
VSAT Antenna Development for Commercial Ka-Band (Rx: 19.2 GHz to 20.2 GHz; Tx: 29.0 GHz to 30.0 GHz). The system is based on an aperture consisting of modular assembled metallized plastic segments.
Manufactured using injection molding and subsequently galvanically metallized, the aperture is formed from an array of horn antennas with overlapping individual apertures.
The planar design allows for a flat antenna profile while providing sufficient gain to support both commercial geostationary communication services and those established with upcoming LEO and MEO constellations.
The active configuration of the receiving aperture compensates for losses in the feed network and enables electronic beamforming through suitable phase control.
Tracking is implemented both electronically and mechanically.
The integrated electronic polarization switching for transmit and receive operation allows for maximum flexibility.
The system has been developed for “On The Move” applications and is specifically optimized for a land-mobile vehicle profile. A low center of gravity and compact design enable high accelerations.
Land Mobile | Planar antenna aperture
- Specification of the aperture area with the aim of minimizing the overall height of the system
- The form factor significantly determines antenna gain and antenna radiation pattern
- Determination of 15 Tx modules and 8 Rx modules, resulting in dimensions of 110cm x 30cm
- Specification of electrical and mechanical interfaces
- Coordination with the aperture supplier (technical, commercial, and logistical)
- Development, manufacturing, assembly, and measurement of the aperture modules
Land Mobile | EBF Implementation
- Active implementation of the Rx aperture to achieve electronic beamforming
- Beam steering through adjustable phase shifts of the 8 Rx sub-modules
- Integration of EBF (Electronic Beamforming) functionality into the antenna aperture and coordination regarding mechanical and electrical interfaces
- Development of high-level drivers for beam steering by a few tenths of a degree by the subcontractor IMST
- Examination of the effects on the antenna radiation pattern in both co-polar and cross-polar planes and optimization as necessary
Land Mobile | Mechanical design
- Implementation of the planar aperture at optimal suspension points for minimum radome size
- Removal of the roll axis to reduce body height and weight
- Inclusion of results derived from vibration tests (e.g. use of closed profiles; preference for bolted over riveted connections).
- Development of a cabling concept for the revised prototype mechanics
- Generation of the individual part manufacturing data from the revised 3D design
- Selection of suitable manufacturers as well as data exchange and coordination of offers
- Assembly of subassemblies from supplied parts and their verification
- Drive via semi-circular roller track
- Drive arches on the back of the aperture
- 2-stage toothed belt drive
- Drive on both sides via central, rigid drive shaft
- Planetary gear and transmission belt with large gear and flat bearing with large hollow shaft
- Stepping motor
- 2-channel rotary joint in U-configuration
- Slip rings
Land Mobile | Radome
- Main task: Protecting the antenna system from environmental influences
- Compromise of mechanical stability, electromagnetic losses and production costs
- Selection of the basic material composition and measurement of selected layer structures
- Determination of the radome set-up after mechanical and metrological evaluation of the candidates in question.
- Adaptation of the radome construction to the final mechanical design and to the chosen manufacturing process
- Generation of CAD data for toolmaking
- Coordination of toolmaking and sample production
- Metrological evaluation of the prototype radome
Land Mobile | System control
- Replacement of the combination of satellite tuner and DVB-S2 demodulator by integrated satellite tuner with DVB-S2X demodulator
- Integration of a second signal processing path consisting of baseband converter, analogue filter stage, high-speed ADC and FPGA for the implementation of pure power-level based tracking
- 10 MHz continuity in the Rx signal path
- Load and temperature tests with ambient temperatures up to 55°C
- No failures detected in the tested electronics during vibration and shock tests
- Integration of a ventilation system inside the electronics
- Extension of the electronics by an RS485 interface to control the active part of the planar aperture
Landmobil | Stromversorgung
- 19″ 1 U form factor for the indoor units
- Further development of the power electronics for generating the voltages of BUC and ODU
- Vibration and shock tests carried out showed no failures or malfunctions of the power electronics
- Extension of the display options in the web interface and display to include diagnostic values from environmental sensors and power supply monitoring
- Selection of a 19 inch 1U rack inverter with 12 V / 24 V input and 220 V / 50 Hz true sine wave output to supply modem, ACU and ODU
- Function test of the inverter in connection with online UPS and other consumers in the laboratory and in the car
- Environmental tests with all components
Land Mobile | Polarizer
- Connection of BUC and LNB to planar aperture
- Design of a waveguide combiner to transmit the output signals of the active Rx electronics to the LNB
- Realisation of circular polarisation in the receive path by means of programmable phase shifting of the two orthogonal waveguide feeds
- Development of a hybrid coupler for feeding the Tx aperture and generating the circular polarisation
- Optimisation of the hybrid coupler to compensate for existing differences in the phase delays of the waveguide networks
- Construction of the mounting concept in coordination with the aperture supplier
- Testing of the feed network of the Rx aperture
- Implementation of high-level functions for polarization selection in the Rx path
Land Mobile | High-speed 3D-Sensor-Module
- Confirmation of the specification and sizing of the hardware for the Inertial Sensor Module
- Revision of the tracking algorithm
- Design of an extended Kalman filter and its implementation into the sensor module
- To offload the system control, the calculation of target angles is done directly in the sensor module
- Integration of a Second Stage Bootloader and support for encrypted Over-The-Air updates
- Software development for conducting fully automated temperature calibrations
- Adjustment of target angle calculations for the modified axis arrangement of the positioner
- Verification of the optimized assembly on the motion simulator and in a motor vehicle.