Abstract: An object is to provide a demodulation circuit having a sufficient demodulation ability. Another object is to provide an RFID tag which uses a demodulation circuit having a sufficient demodulation ability. A material which enables a reverse current to be small enough, for example, an oxide semiconductor material, which is a wide bandgap semiconductor, is used in part of a transistor included in a demodulation circuit. By using the semiconductor material which enables a reverse current of a transistor to be small enough, a sufficient demodulation ability can be secured even when an electromagnetic wave having a high amplitude is received.

Abstract: An object is to provide a demodulation circuit having a sufficient demodulation ability. Another object is to provide an RFID tag which uses a demodulation circuit having a sufficient demodulation ability. A material which enables a reverse current to be small enough, for example, an oxide semiconductor material, which is a wide bandgap semiconductor, is used in part of a transistor included in a demodulation circuit. By using the semiconductor material which enables a reverse current of a transistor to be small enough, a sufficient demodulation ability can be secured even when an electromagnetic wave having a high amplitude is received.

Abstract: A monolithic direct digital UHF/L-Band receiver for receiving and processing a UHF/L-Band analog signal and deriving digitized samples, the receiver operating in a tuning frequency range centered at a center frequency and having a baseband frequency, a lower bandedge frequency, and an upper bandedge frequency. The receiver comprises: a substrate; an analog-to-digital converter, mounted on the substrate, for digitally sampling at a sample rate the UHF/L-Band analog signal; a heterodyning circuit, coupled to the analog-to-digital converter and mounted on the substrate, for mixing the digitally sampled signal with a mixing signal thereby shifting the center frequency of the tuning frequency range of the sampled signal to the baseband frequency; and means, coupled to the heterodyning circuit and mounted on the substrate, for decimation filtering and decimating the mixed signal to obtain a second sample rate lower than the sample rate.