Specifications:
| Frequency Range: | 0.01 … 120 MHz |
| Loop Diameter: | 100 mm |
| Number of Turns: | 3 |
| Connector: | BNC (N by request) |
| Mount: | Camera Thread 3/8"; 16 mm |
| Material: | Brass, Nickel plated |
| Dimensions: | 158 x 112 x 45 mm |
| Weight: | 250 g |
| Scope of Delivery: | HFRA 5164, HFRA-Spacer50 |
| Maximum Coil Current: | 12 A (5 min.) |
| Max. Cont. Current: | 8 A |
| Magnetic Fieldstrength with 1 A Coil Current at 50 mm Distance: | 10.61 A/m |
| Magnetic Fieldstrength with 1 A Coil Current at Loop Center: | 30 A/m |
| kH (nominal): | 0 – 35 dB/Wm |
| kE (nominal): | 52 – 87 dB/m |
Description of Shielded Loop Antenna HFRA 5164
Overview
The shielded loop antenna HFRA 5164 is designed to generate magnetic fields for immunity tests from a few kHz up to 120 MHz. A typical application is immunity testing for medical equipment according to IEC 61000-4-39, from 150 kHz to 26 MHz, where the transmit loop antenna is located 50 mm from the Equipment under Test (EuT) surface.
Features and Applications
- Special Fixture for EuT Testing: The HFRA 5164 includes a special fixture (HFRA-Spacer50) that clamps the 16 mm shaft of the loop antenna and provides the necessary spacing from the EuT surface.
- Direct Connection to Power Amplifiers: The transmit loop is designed to connect directly to the 50 Ω output of a class-A power amplifier.
- Field Monitoring: For monitoring the generated fields, the shielded monitoring loop FESP 5134-1 is recommended. This loop can interface directly with 50 Ω measuring equipment. With the optional Loopholder 5164-39, the small sensing loop can be clamped on the transmit loop at a distance of 50 mm without tools, allowing simultaneous monitoring of the generated field strength during immunity tests.
Design and Performance
- Electrostatic Shielding: The electrostatic shield provides outstanding symmetry and strong rejection of unwanted parasitic E-fields, eliminating the need for sheath current suppressors.
- Economic Field Generation: For generating magnetic fields in the RFID frequency band at 13.56 MHz, the NFCN 1356 compensation network is available, tailored specifically for the HFRA 5164. This network achieves optimal impedance matching in the RFID band, resulting in significant power savings. A typical magnetic field strength level of 26 A/m with 50 W power can be achieved at a distance of 50 mm at 13.56 MHz for short periods (1 minute).
Operation as RX Loop Antenna
The HFRA 5164 can also be used as an RX loop antenna connected to 50 Ω measuring equipment. It measures the magnetic field strength, and the voltage across 50 Ω must be added to the antenna factor kH to obtain the magnetic field strength in dBµA/m. For far-field measurements, add the conversion factor for E-fields (kE) in dB/m to the receiver’s measured result in dBµV to obtain the fictitious E-field strength in dBµV/m. The conversion from magnetic field strength to fictitious electric field strength does not depend on the frequency and is 51.5 dB (=20 log (377 Ω)).
