Search

Compact antenna test ranges are used for fast and accurate measurement of satellite antennas and payloads. The measured performance of compact range feed dictates the quality of Quiet zone at CATF. A Dual Linear Q/V-Band feed compliant to standard compact range feed specifications was designed. The designed feed will be used for RF characterization of advance communication payload. In this paper, design aspects and simulated results of proposed feed are discussed.

Compact antenna test ranges are used for fast, precise and real time measurement of antenna and payload parameters. ISRO has established a Compact range at Bangalore and has a rich experience of characterizing more than 33 satellites and 200 subsystem level antennas over wide frequency range from 1–40 GHz. The standard set of compact range feeds comprises 7 dual linear polarized and 2 single linear polarized feeds in the range of 1–40 GHz. In case of satellites with payloads in lower C, Nor C and Upper ext. C-band, 3 compact range feeds should be used for performing payload characterization which consumes considerable test set up time. In this view, an ultra-wide C-band (65% Bandwidth) is designed covering the above mentioned frequency bands. In this paper, design methodology and simulation results of the proposed feed are presented.

Spacecraft when placed in plasma, spacecraft charging occurs which results in ESD discharge. This paper focuses on ESD fields radiated in spacecraft level and the noise coupled to a nearby wire when it is exposed to these radiated fields. A dipole model is considered to predict the transient radiated fields. The ESD current data is experimentally obtained in order to obtain the noise coupled to nearby wire. Furthermore, telegrapher's equations have been employed to compute the induced current and voltage. Additionally, the fields radiated and noise coupled to the wire under various conditions are computed and plotted.

This paper presents a computation of the absolute free space capacitance and electrostatic body potential of a spacecraft using moment method with triangular patch modeling. Expressions are derived numerically and the moment integral is evaluated. The capacitance of a square plate is computed to validate the approach. Finally, the free space capacitance of a typical spacecraft is computed for various configurations and body potential is evaluated. The derived expressions are simple and suitable for developing the charging analysis tool. As this approach is more general, it can be easily applied to any practical spacecraft configuration.

The MARS Orbiter Mission (MOM) spacecraft carries on-board sensitive receiver and high gain antenna system to cater to the requirement of inter-planetary and deep space communication. This paper describes, among others, the stringent EMC requirements for MOM spacecraft, summary of EMC analysis carried out, modification on subsystem level EMI/EMC test limit and EMI/ESD mitigation techniques followed to achieve EMC compliance of MOM Spacecraft.

The external surfaces of a spacecraft exposed to Earth's magnetospheric plasma can build up differential voltages which can result in an electrostatic discharge (ESD). This discharge may induce transient electromagnetic interference (EMI) in the electronics circuitry and may give rise to switching anomalies or system failure under certain environmental conditions. This paper outlines the development of Lumped Element Model (LEM) of a spacecraft for surface charging studies. A numerical solution procedure using method of moments and triangular patch modelling to determine the capacitance of conducting objects in free space has been developed. Differential equations of spacecraft charging have been derived and the surface charging of INSAT-2E spacecraft has been simulated. The results obtained for INSAT-2E using LEM concept are compared with those obtained using the NASA Charging Analysis Program (NASCAP) for a similar satellite.Using LEM of a conducting plate located in free space, and with the help of cir...