Changes

[[NeoScan]]® real-time field measurement and scanning system is a turnkey, electric or magnetic field probe and measurement system. It can be configured as a near-field scanning system for mapping aperture-level field distributions with minimal invasiveness to the device or system under test. Or it can be used as a real-time field probe system for sensing or detecting electric and magnetic fields in a variety of media.

[[NeoScan]] provides detailed field maps of passive and active devices and circuits including RFIC’s and MMIC’s. Such invaluable information can effectively be used for design validation, model verification, diagnostics and fault isolation or performance evaluation of various parts of RF systems. It is also an alternative compact range for measurement of far-field radiation patterns of antennas and arrays, dispensing with a costly anechoic chamber. The system can be used in real-time, polarimetric and coherent sensing and probing of wideband signals and pulses, EMC/EMI testing, and medical device measurements and characterization of biological environments. The [[NeoScan]] system can be configured in a multi-channel architecture for simultaneous field measurement at multiple points and locations. Different channels can measure different polarizations in a coherent manner.

Wideband operational bandwidth: few MHz to 20GHz, measuring repetitive signals with 50-ps rise time, 10-ns duration, and 80 V/m amplitude with a 10% to 90% definition

System Operation, Monitoring, and Optimization Software

The [[NeoScan]] real-time field measurement & scanning system provides an entirely new capability for the measurement of high-intensity electric fields. This technology is based on the Pockel’s effect which measures the phase-retardance of an optical beam due to an impinging electric field. This electro-optic effect is observed in non-centrosymmetric crystals when an electric field is directed along certain crystal axes causes a change in the indices of refraction encountered by an incident optical beam. Figure 1.1 shows the basic principle of the electro-optic effect. The electro-optic effect provides a means of modulating the phase or intensity of the optical radiation. In another sense, this effect also makes it possible to detect the presence of an electric field impinging on the crystal. The polarization of an optical beam travelling through a crystal is altered by the electric field in that crystal. The comparison of polarization states allows determination of the amplitude and phase of the existing RF electric field. Since the electro-optic sensing phenomenon relies on small displacements of the atomic crystal structure, the response time of the process is extremely short. This short response time makes it possible to measure high-frequency electric fields up to the terahertz regime.

The [[NeoScan]] system is capable of measuring signals with bandwidths up to 20 GHz and signal levels as low as 1 V/m for optical probes with a 10 m PM fiber. Because the optical probes are free of metallic parts, it is possible to measure extremely high-field strengths since there are no free electron surfaces to generate arcing. The [[NeoScan]] can measure fields up at least 2 MV/m and possibly higher.

The [[NeoScan]] real-time field measurement and scanning system consists of:

The front panel is the main interface to the system. It contains a control computer that that runs Microsoft Windows, and controls, commands, and monitors the [[NeoScan]] system’s status (Figure 1.7).

The rear panel is the interface to the instruments and provides complete access for external control, optical fiber excitation, and RF signal output (Figure 1.8). It contains:

An electric fan

 

2D: 2-dimentional

V: Volt

The [[NeoScan]] system contains extremely sensitive and fragile components. Use extreme caution whenever operating this system. Do not attempt to service or adjust or install substitute parts to its components. Please contact EMAG Technologies Inc. for service and more information.

While holding the probe from its glass tube and keep the fiber sheath in your hand, avoid stretching the white plastic shield part of the fiber. Do not pull the plastic shield part hard.

The Probes and the fibers are made of a very pure, sensitive, and expensive materials. Treat them with care. Unwind a fiber gently and work out any tangles carefully.

Remove the protective cap on the optical fiber cable connector. Connectors should be cleaned before interconnection. Any dirt or contamination can damage the connector or degrade performance. In other words, fiber optic connectors should to be cleaned every time they are mated and unmated. Use a dry cleaning cloth (reel-based cassette cleaner) to remove dirt, dust, and oil from connector end faces (Figure 2.5). You can also carefully clean a dirty fiber connector with isopropyl alcohol (IPA) and then dry with FIS fiber optic cleaner.

The probe is coupled with a 10-meter-long PM fiber and connects to the optical mainframe with a FC/APC optical fiber connector. Remove the APC protection caps and keep safe for reuse when repacking the instrument. Gently clean and attach the appropriate fiber connectors to the correct fiber ports of the [[NeoScan]] system. There is a pre-aligned (slow or fast axis) adjustable key connectors for the PM axis alignment across a connection. Make sure the key is aligned in the slot properly before tightening, see Figure 2.6.

As a quick system test:

When the program starts, the system should detect the total return power and polarization power and display their graphs over time and show their numerical values in mW, see Figure 2.8. The green “Probe Detected” indicator light will indicate that the probe is connected to the correct channel. Otherwise, if either the total return power or the polarization power is too low (less than 0.3 mW), the information panel will remind the users to correct the problem. This can be the case if the probe is not connected or is defective or there is a problem with the [[NeoScan]] system (Figure 2.9). Select the channel number you want to check using the dropdown list labeled “Select Channel.”

During the scan or optimization process, the probe will be mounted on a plastic probe fixtures. The plastic probe fixtures has been mounted on translation stage by a single cap screw and holds the probe (Figure 2.10). The probe is positioned inside the gap located on probe holder and is secured by a cap which is fastened by screws as shown in Figure 2.11.