Co-site interference analysis. Marli Strydom CST AG

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1 Co-site interference analysis Marli Strydom CST AG

signal reception = Cosite Interference Desired Signal Undesired Emitters Victim Rx

2 The Cosite Scenario Victim Rx trying to hear desired signal from remote Tx At the same time, local emitters are transmitting Emitters can interfere with desired signal reception = Cosite Interference Desired Signal Undesired Emitters Victim Rx THE GOAL: predict the potential for cosite interference for all Rx s in the scenario.

3 The Co-Site Problem Multiple RF systems co-located in a common environment Diverse system characteristics Frequency bands (10 KHz to 40+ GHz) Power levels Modulation types Multiple EMI coupling paths Antenna coupling Cable coupling Circuit coupling

Mechanisms for Cosite Interference There are many mechanisms for coupling

Radiated Coupling can be direct between a Tx and Rx Or it can be more complex Or

, rusty bolt effect) Non-linear interactions generate additional spectral

4 Mechanisms for Cosite Interference There are many mechanisms for coupling between the Tx s and the Rx: Antennas Cables Enclosures Conducted vs. Radiated Coupling can be direct between a Tx and Rx Or it can be more complex Or even devious! (e.g., rusty bolt effect) Non-linear interactions generate additional spectral components (Intermodulation) Emitter signal spectra contain both narrowband (NB) and broadband (BB) signal components Signals in-band and out-of-band must be considered

5 The Conceptual Solution: Cosite EMI Many methods to achieve EMC Antenna placement, type Decreased transmit power levels Adding filters Replacing defective hardware Frequency planning

6 Predicting Cosite EMI The biggest challenge in making useful cosite EMI predictions lies in managing all of the input data, models, output data, and results. Availability of input data varying types and fidelities Cosite evaluation usually cannot wait on high-fidelity system data Data management and cosite models must allow incremental refinements Result post-processing is critical for identifying and mitigating cosite EMI problems.

7 EMIT EMIT provides an approach to data management and simulation for cosite EMI predictions.

8 Inputs for an EMIT Analysis Antenna models Aircraft geometry (CAD) RF component models Radio emissions and susceptibility models

9 Co-Site Interference Workflow Antenna synthesis Antenna coupling Co-site EMI

10 Predator Co-Site Analysis GPS elliptical patch GHz UHF blade 320 MHz VHF blade MHz IFF2 monopole MHz IFF1 monopole MHz

11 Broadband Multi-Port Coupling

12 Installed Patterns 60 MHz 320 MHz 1.06 GHz 1.06 GHz GHz

managing system performance data, simulating

13 Delcross EMIT Co-Site Tool Tx Emissions Antenna Coupling Rx Vulnerability Software framework for managing system performance data, simulating intra-system EMI effects and mitigating EMI issues Component Characteristics

14 Conclusion Emit is a system management tool Multi-fidelity quality inputs can be used EMI prediction can start at early level of project As input fidelity increases, so do the EMI prediction

15 Multi-Fidelity Coupling Models Constant Coupling - constant Path Loss - free-space path loss (distance) Path Loss + Gain - computed from the path loss and the antenna gain in the direction between antennas. S-Parameters - wideband coupling from user-supplied S-parameters (from measurements or CST STUDIO SUITE) (db) S-Parameters Fixed Value Path Loss Path Loss & Gain

EMIT Library EMIT Library currently provides multiple models of typical radios of interest to military and commercial users Each model is notated with specific details of the system Representative

16 EMIT Library EMIT Library currently provides multiple models of typical radios of interest to military and commercial users Each model is notated with specific details of the system Representative models for outboard components are also provided The Library content will continue to be enhanced and updated Users can create and maintain their own databases of systems and components in custom libraries Libraries can be exported for sharing with other users

Prediction of Co-site interference in complex RF environments

Prediction of Co-site interference in complex RF environments Frank Demming-Janssen CST AG The Cosite Scenario Multiple RF systems co-located in a common environment Diverse system characteristics Frequency