Trouble-free operation of antenna systems

Specialist field: Electromagnetics

The Kopter Group is developing a new generation of helicopters. These helicopters are equipped with a variety of antenna systems for communication purposes. Electromagnetic simulation helps to avoid interference in order to ensure clear transmission and reception behaviour.

Summary
Task
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Summary

Task

A large number of high-frequency systems are integrated in the latest generation of helicopters. Malfunctions due to electromagnetic interference (EMI) are to be excluded as far as possible in the early development phase. For this purpose, an interference analysis should be used to identify an optimal configuration of the antenna systems.

Solution

With the help of ANSYS HFSS and ANSYS HFSS SBR+, a targeted investigation of the radiation and reception behaviour of the various VHF antennas as well as their interaction with each other was carried out. In addition to the investigation of the antenna behaviour in the near field, the determination of the EMI matrix was particularly important. The comparison of different layouts made it possible to select the best possible antenna configuration.

Customer benefits

By the numerical consideration of the system behavior already in the early development stage

significantly accelerates development,
the best possible positioning of the antennas,
while at the same time minimizing possible misconduct.

Project Details

Task

Kopter Group was founded for developing, building and supporting a new generation of turbine helicopters. With this industrial vision, Kopter Group developed the SH09, guaranteeing to the operator superior operational performance, safety and life cycle economics that make the difference.

A modern helicopter needs a large number of high frequency (HF) systems for communication and other purposes. Malfunctions caused by electromagnetic interferences (EMI) of the different HF-systems, have to be avoided. To save time and costs, an interference analysis was performed using the software Ansys HFSS (SBR+ solver, formerly Savant; EMIT) in an early stage of the project to choose the best possible positions of the different antennas.

Visualization of the shooting and bouncing rays for one specific VHF antenna (only electromagnetic rays, which bounce on the helicopter surface are shown).

Customer Benefits

Studying different antenna arrangements, the best possible positioning layout could be identified without the need of lengthy testing and rearranging of the antennas on the fuselage, which would be very costly in terms of time and money. Therewith, the development process could be substantially accelerated by simultaneously minimizing the risk of malfunctions of the HF-systems.

Installed radiation pattern of the different antennas on the SH09 helicopter.

Solution

To ensure interference free operation for all HF-systems, antennas and radios (including filters) have to be chosen appropriately. The radiation patterns for the antennas installed on the fuselage (Fig. 2) and the coupling matrices for each antenna pair were computed using a shooting and bouncing rays algorithm (Fig. 3). Additionally, the radio types were incorporated in the model, allowing for realistic EMI margins (margin to a disturbing interference event). The EMI margins matrix for every antenna pair was computed (Fig. 4) and compared for several antenna layouts. With this investigation the optimal locations for the miscellaneous antennas could be found.