UNDERGROUND ANTENNA Russian patent published in 1998 - IPC

FIELD: radio engineering; underground antennas operating in high-frequency band. SUBSTANCE: antenna has two tiers of dipoles placed in holes 4 drilled in semiconducting soil 2 symmetrically on either side of bin 1 which is also placed in soil and surrounded by metal screen 3. Each side of dipole is built up of two coaxial pipes 5,6 joined by means of insulating insert 7. Sides are connected to outputs of power splitters 12 and 13 between dipoles of first and second tiers, respectively. Output of transmitter 9 is connected to tier-to-tier power splitter 10 whose first output is connected through phase shifter 11 to output of first-tier power splitter 12 and second output, directly to input of second-tier power splitter 13. Optimal relations between antenna structural members are given in description of invention. Antenna gain in operating frequency band is 4-6 dB higher than that of its prototype. EFFECT: improved gain without increasing antenna area. 2 cl, 7 dwg