Pillbox antenna for ADS-B 1090MHz reception

Pillbox antenna for ADS-B reception at 1090MHz, started as proof of concept design, gone through 3D modeling and optimization and final measurements on a prototype built.

Theory #

Concept and initial design in Antenna Magus (where it's called a probe-fed cheese antenna)

Simulation in CST

Reality #

Final build dimensions

Diameter Dr: 550 mm
Height Hr: 100 mm
Focal depth F: 115 mm
Spacing wire probes Swp: 30 mm
Length feeder probe Lwp: 60 mm
Length reflector Lwr: 100 mm
Wire diameter probes Dw: 3 mm
Sheet metal: calvanized steel, thickness 0.2 mm
Feed probe and reflector: 3mm brass tube
Feed socked: N type flange mount

Download drawing for top and bottom sheet.

Cut along the dashed line in drawing. Bend along the solid line.

Soldered from inside. The 100 mm wide reflector sheet goes along the solid line.

See drawing for reference.

Feed point outside. Reflector probe is soldered on top and bottom sheet.

Impedance measurement results #

Gain measurement results at 1090 MHz #

The directivity gain has been measured using the gain transfer method.

Maximum directivity gain 7.93 dBi at azimuth 0° and elevation 0°
Main 3 dB horizontal beam width (elevation 0°): ~27°
Side lobe 3 dB horizontal beam width (elevation 0°): ~99°
Main 3 dB vertical beam width (azimuth 0°): ~128°

Test setup:

Test antenna: AINFO Octave Horn Antenna LB-OH-650-15-C-NF 1.0-2.0 GHz
Reference antenna: Schwarzbeck RS-0460, 0.53 dBi @ 1090 MHz
Test receiver with tracking generator: R&S ESRP7, RF output power 0 dBm
Distance test antennas: 10 m (far field conditions)
Azimuth test range: -110° to 110° @ elevation 0°
Elevation test range: -90° to 90° @ azimuth 0°

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