Patent ID: 7741856

Claim:
An immunity test system for determining an immunity of a piece of electronic equipment as a test object by irradiating the electronic equipment with a test wave, the immunity test system comprising: an antenna that emits the test wave toward the electronic equipment; a signal generator having a first amplifier, and the signal generator generating a transmission signal through the first amplifier to cause the antenna to emit the test wave; a level adjusting device that adjusts a signal level of the transmission signal inputted from the signal generator to the antenna by controlling a gain of the first amplifier; a boundary point detection device that chances the signal level of the transmission signal inputted to the antenna through the level adjusting device while monitoring operation of the electronic equipment, and thereby detects a signal level of the transmission signal at a boundary point at which the electronic equipment is changed, due to the test wave, from a normal operation state to an abnormal operation state or from an abnormal operation state to a normal operation state; and a test result storing device that calculates an electric field strength of the test wave irradiated to the electronic equipment, at the boundary point, by using a predetermined conversion data based on the signal level of the transmission signal at the boundary point detected by the boundary point detection device, and stores a calculation result of the electric field strength as well as a test condition used for obtaining the electric field strength in a storage device, thereby allowing an evaluation of the immunity of the electronic equipment; wherein the antenna is a horn antenna, and one end of the horn antenna is connected to a first waveguide having a rectangular shape cross-section; the test wave is emitted from the first waveguide toward the electronic equipment; a second waveguide is connected to the other end of the horn antenna; a first probe is arranged within the second waveguide and is provided with the transmission signal for emitting the test wave; a second probe for feeding the transmission signal to the first probe; and a third waveguide for forming a power feed path for the transmission signal from the second probe to the first probe.