SPIRAL ANTENNA WITH READJUSTABLE RESONANCE FREQUENCY Russian patent published in 2004 - IPC

FIELD: antenna equipment, ultra short and decimeter waves radio communication systems.

SUBSTANCE: spiral antenna with readjustable resonance frequency includes elements functioning as radiator: dielectric base carrying emitting winding put on it, aerial distributed capacitor of variable capacitance formed by one or several metal bars positioned along axis of dielectric base and emitting winding. Given antenna has elements functioning as matching tuned transformer with primary and secondary windings positioned on dielectric base. Finish of primary winding and start of secondary winding are interconnected, cylindrical capacitor of variable capacitance comprises mobile outer metal plate connected to metal bars, dielectric insulator, inner metal plate connected to start of primary winding. There are positioned metal guiding contact bushing made fast to dielectric base between start of emitting winding and finish of secondary winding interconnecting them electrically and through metal bars to mobile outer metal plate. Possibility of readjustment of resonance frequency of spiral antenna is ensured by simultaneous movement of metal bars of distributed capacitor of variable capacitance and mobile metal plate of cylindrical capacitor of variable capacitance along vertical axis of primary and secondary windings and radiator winding in correspondence with direction of readjustment of resonance frequency of spiral antenna which leads to optimal matching in wide frequency range.

EFFECT: design of spiral antenna displaying optimal matching during readjustment of resonance frequency in wide frequency range.

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