Bicone, discone, bicone-log

Overview

Wideband antennas for EMC testing and radio monitoring. A rod frame instead of a solid cone, a balun and a matching network, the bicone-log: a biconical part and log-periodic dipoles on one base. The antenna factor is calculated too.

From the simplest to the most complex: a 100–1000 MHz discone, up to a 30 MHz – 1 GHz or up to 6 GHz bicone-log with a rod bicone, a balun, a matching network and over 30 dipoles of the log-periodic part.

Typical performance

• Band: bicone and discone ≈ 10 : 1 (30–300 MHz, 100–1000 MHz), bicone-log ≈ 30 : 1 (30 MHz – 1 GHz)typical
• VSWR < 2 over most of the band; higher at the lower edge, so a matching network is neededtypical
• Gain: bicone and discone ≈ 0–3 dBi, bicone-log ≈ 3–7 dBitypical
• Linear polarisation; bicone and discone omnidirectional in the plane, bicone-log directionaltypical

Typical values describe the antenna class, not a guarantee for a unit; “computed” marks our own simulated example.