Abstract: A linear power amplifier and method for removing the intermodulation distortion with a predistortion system and a feed forward system. The linear power amplifier having a main power amplifier includes: a predistortion system for firstly suppressing the intermodulation signal generated upon amplification of an RF signal in the main power amplifier, by generating a harmonics corresponding to the input RF signal and a predistortion signal with coupling the RF signal to the harmonics; and a feed forward system for secondly suppressing the intermodulation signal by canceling the input RF signal and the output of the main power amplifier, extracting an intermodulation signal distortion, error-amplifying the extracted intermodulation signal distortion, and coupling the amplified intermodulation signal with the output of the main power amplifier.

Abstract: A UV irradiation apparatus, which includes a UV lamp installed in a chamber for generating UV rays; a vacuum chuck installed below the UV lamp for supporting and moving a wafer; and, a reflector surrounding the UV lamp for concentrating UV rays on the vacuum chuck. The apparatus further includes heating blocks for controlling the temperature at both sides of the vacuum chuck. Thus, it is possible to maintain an essentially constant temperature around the wafer supported by the vacuum chuck. As a result of the temperature control, when a protection tape attached to the front side of the wafer is irradiated with UV rays, an adhesive of the protective tape can be effectively degraded by a chemically reaction under optimum conditions, to thereby easily detach the protection tape from the wafer.

Abstract: A radio frequency power combiner includes a plurality of transmission lines connecting a plurality of input terminals to an output terminal. An RF switch is positioned between each of the input terminals and a transmission line connecting the output terminal to the input terminal. The electrical length between each RF switch and the output terminal is preferably one half of a wavelength at a central frequency, which may be realized by two transmission lines of different impedances in each path, each a quarter wavelength long. When the switches are on, the signal power applied to all of the input terminals is combined at the output terminal. When any given switch is turned off, the RF power incident to the switch is reflected, and the transmission lines connected between that switch and the output terminal appear as an open circuit. The power combiner can also operate as a power divider.

Abstract: An overheat prevention circuit for an electromagnetic induction heating cooker. The electromagnetic induction heating cooker has a heating coil, a top plate disposed over the heating coil, on which an object to be heated is laid, a temperature sensing part for sensing a temperature of the object and a high-frequency power generation part for generating a high-frequency magnetic field to the heating coil to induction-heat the object.