Characteristics Analysis for the Spherical Antenna of A Seismometer

摘要

A seismometer for vertical electric field component of natural ELF and ULF electromagnetic waves measurement by using spherical antenna is introduced. The goal of the proposed seismometer is to provide continuous observation of the natural electromagnetic emissions related to the coupling of seismic activity with the outer spaces and ionosphere, which utilize a spherical aluminum electrode 78 mm in diameter with embedded enhanced preamplifier circuits that built to mount flush with the ground so as to preserve the configuration in which the antenna operates. The presented seismometer has a wide frequency response at low frequencies, it's typical sensitivity in the frequency range DC to 30 MHz are shown to be 2.2 uV/m (Hz)~(1/2)@10 KHz and 0.034 uV/m (Hz)~(1/2) @5 MHz, the dynamical range is >50 dB in ELF and VLF and about 25 dB in HF.