Electromagnetic interference/electromagnetic compatibility (EMI/EMC) prediction models and techniques, and analysis tools are being widely developed and used for radio frequency systems. However, given that electro optical (EO) and infrared (IR) systems also utilise the electromagnetic spectrum, it is important that the EMI/EMC concept should also be extended to incorporate EO and IR systems. There are currently no prediction models and technique or analysis tools available to assess EMI/EMC of EO and IR systems. This paper presents an EMI/EMC modelling prediction method, which has been applied on a number of test cases to assess EMI/EMC for EO and IR systems.
Modern ships have numerous installed radio frequency (RF) systems and, as a consequence, there is a high likelihood of electromagnetic interference (EMI). To analyze RF systems EMI and electromagnetic compatibility (EMI/EMC), computational electromagnetic (CEM) modeling is often used. However, using CEM can be challenging due to a number of reasons, such as computational cost, associated with simulation time and computer memory, and obtaining sufficiently high accuracy, associated with simulated results. Computer memory cost and obtaining high accuracy are significant challenges for ship EMI/EMC, because it becomes an electrically large problem at GHz frequencies. This paper will provide an overview of a methodology to analyze high-frequency (=1GHz) ship EMI/EMC, using CEM, while maintaining reasonably high accuracy and reducing the computer memory cost.
This paper assesses the validity of using numerical modelling to estimate the out-of-band antenna coupling of microwave antennas. In this paper the out-of-band antennas modelled were installed on a 3U nanosatellite, and the coupled (or received) power, Pr was determined via two different approaches using a Method-of-Moments technique. One approach was to compute the coupled power at the receive antenna port due to a known transmit power at the transmit antenna port. The second approach involved calculating the averaged power density in a near-field region in close proximity to the receive antenna due to the transmit antenna, and an "average" effective antenna response due to out-of-band frequencies. The coupled power, determined using both approaches was compared to analytical coupling estimations, and the results were in good agreement.
This paper discusses the effects of different types of radio frequency interferences on the radar receiver of a navigational X-band radar as displayed on the plan position indicator (PPI). In particular, this paper deals with the theoretical analysis of the predicted field strength of the envisaged measurement set-up followed by the description of the actual set-up and discussions on the observations and achieved results. The experimentation set-up in pursuit of specific user requirements include a radio frequency interference source placed in the near-field of the rotating radar antenna and an examination of the effects on the genuine target display on the PPI. For pulsed interference signals, the interferences appear as short radial lines on the PPI display causing confusion with genuine target echoes. For continuous wave (CW) interference signals the receiver noise level is elevated resulting in the loss of sensitivity and degraded radar detection performance.
The free-space antenna near-field region, which is typically large in magnitude, could be increased further when an antenna is placed close to an electrically large structure. Any increase in the near field region can in turn impact any near-field power density assessment associated with human exposure and protection from electromagnetic radiation and cosite interference. This paper compares an estimation of the on-axis and off-axis near-field power density of a linear array antenna in free space with that when placed close to an electrically large structure to determine what effect an electrically large structure may have on an antenna's near-field power density.
'/%3e%3c/defs%3e%3cpath fill='%23012169' d='M0 0h10080v5040H0z'/%3e%3cpath stroke='%23fff' stroke-width='.6' d='m0 0 6 3m0-3L0 3' clip-path='url(%23b)' transform='scale(840)'/%3e%3cpath stroke='%23e4002b' stroke-width='.4' d='m0 0 6 3m0-3L0 3' clip-path='url(%23c)' transform='scale(840)'/%3e%3cpath stroke='%23fff' stroke-width='840' d='M2520 0v2520M0 1260h5040'/%3e%3cpath stroke='%23e4002b' stroke-width='504' d='M2520 0v2520M0 1260h5040'/%3e%3cg fill='%23fff'%3e%3cuse xlink:href='%23d' x='2520' y='3780'/%3e%3cuse xlink:href='%23a' x='7560' y='4200'/%3e%3cuse xlink:href='%23a' x='6300' y='2205'/%3e%3cuse xlink:href='%23a' x='7560' y='840'/%3e%3cuse xlink:href='%23a' x='8680' y='1869'/%3e%3cuse xlink:href='%23e' x='8064' y='2730'/%3e%3c/g%3e%3c/svg%3e)
'%3e%3ccircle r='20' fill='%23008'/%3e%3ccircle r='17.5' fill='%23fff'/%3e%3ccircle r='3.5' fill='%23008'/%3e%3cg id='d'%3e%3cg id='c'%3e%3cg id='b'%3e%3cg id='a' fill='%23008'%3e%3ccircle r='.875' transform='rotate(7.5 -8.75 133.5)'/%3e%3cpath d='M0 17.5.6 7 0 2l-.6 5L0 17.5z'/%3e%3c/g%3e%3cuse xlink:href='%23a' transform='rotate(15)'/%3e%3c/g%3e%3cuse xlink:href='%23b' transform='rotate(30)'/%3e%3c/g%3e%3cuse xlink:href='%23c' transform='rotate(60)'/%3e%3c/g%3e%3cuse xlink:href='%23d' transform='rotate(120)'/%3e%3cuse xlink:href='%23d' transform='rotate(-120)'/%3e%3c/g%3e%3c/svg%3e)