Isotropic Omnifield Antenna® OFA-G 30MHz-6GHz

Omnifield Antenna® Model: OFA-G

OFA-G_with SA in hand_2

A unique broadband active E- field isotropic (spherically isotropic) antenna for RF spectrum monitoring. Connects to any spectrum analyzer, and has frequency response practically independent of antenna orientation or electric field direction. Offers high sensitivity and broad dynamic range for the variety of RF regulatory, safety, EMC, wireless and telecommunications applications.  This antenna is very similar to previous generation OFA-S/SE antennas but has about 12 dB higher dynamic range, extends frequency range to 6 GHz and has much smaller size and weight.


Omnifield Antenna® consists of three parts: antenna head, handle and power unit. Antenna head and handle comprise a single module while power unit is detachable from the handle to allow convenient storage in the supplied rugged plastic case. For normal operation handle must be connected to the power unit to provide power to the antenna head.  Antenna head has 3 antennas positioned normal to each other.  Signals from each antenna are combined and amplified to allow utput signal of Omnifield Antenna® to be proportional to the absolute value of the field regardless of the field direction.  Power unit contains the rechargeable battery and connectors for the antenna and output cable. Ferrite beads, located on this cable, decouple the antenna from spectrum  analyzer and reduce the effects of this analyzer on measured field. This cable also allows operator to have freedom to place the antenna in right position either on non-metal table tripod (supplied with every system) or onto optional 5 feet adjustable tripod.




OFA-G_with PU_side view    

Omnifield Antenna® OFA-G

      • Portable isotropic 3-axis EM field antenna with broadband response.
      • Wide field dynamic range: 5 mV/m – 50 V/m.
      • Noise Level ~0.3 mV/m (BW 3 KHz)
      • Broad frequency range: 30 – 6000 MHz.
      • Probe directivity:
      • Calibration accuracy: +/- 1.5 dB.
      • Linearity deviation +/- 1 dB.
      • Rotational isotropicity (typ.): +/- (1-2.5) dB (30 – 1000 MHz),
      • +/- (2-5) dB (1000 – 6000 MHz).
      • Recommended SA bandwidth:  10 KHz ( min BW 3 KHz )
      • Design: Antenna head is mounted on nonmetal handle with detachable output connector.
      • Operating temperature: -10 C° to 50° C, RH 10%-90%, non-condensing.
      • Temperature error: <0.08 dB/°
      • Dimensions:  Antenna: (LxD) 9.0”x2.25” (225×58 mm).

Power unit: (LxWxD), 3.75”x2.25”x1.25” (95x58x32 mm).

      • Weight: Antenna: 0.23 lb. (110 g), Power Unit: 0.44 lb. (200 g).
      • Battery operation time: 10 hr. NiMHd rechargeable battery.

Charge, fast charge and low battery indicator.


      Every system: antenna, low loss 5 ft. cable     and power module are calibrated together. UK NPL traceable calibration certificate is supplied with each unit.

Note: This Specification may be changed without notice due to continuous improvement of the design and manufacturing process.



Calibration Details: Isotropic Antennas Calibration

– Keep unit calibrated. We recommend calibration once a year in our UK NPL traceable EMC Test Lab.

1) Antenna Factors (AF) at  specified frequencies in the frequency range

30 MHz-6000 MHz (@ 5 V/m)

2) Antenna Rotational isotropicity at every frequency.

3) For Selective Spectrum Analyzer we provide a memory card with AF data.

– To convert the electric field strength E (V/m) into power density S (uW/cm2) use formula: S=E2/3.77. To calculate the value of the magnetic field H (far field region) use the relationship: E/H=377 Ohm.





EMC Test Design, LLC®,P.O. Box 600532, Newton, MA 02460, USA.

,, 508-292-1833




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