This paper presents a first monolithic RF transceiver for DC-OFDM UWB applications.The proposed direct-conversion transceiver integrates all the building blocks including two receiver(Rx) cores,two transmitter (Tx) cores and a dual-carrier frequency synthesizer(DC-FS) as well as a 3-wire serial peripheral interface(SPI) to set the operating status of the transceiver.The ESD-protected chip is fabricated by a TSMC 0.13-μm RF CMOS process with a die size of 4.5 x 3.6 mm~2.The measurement results show that the wideband Rx achieves an NF of 5-6.2 dB,a max gain of 76-84 dB with 64-dB variable gain,an in-/out-of-band IIP3 of-6/+4 dBm and an input loss S_(11) of<-10 in all bands.The Tx achieves an LOLRR/IMGRR of-34/-33 dBc,a typical OIP3 of+6 dBm and a maximum output power of -5 dBm.The DC-FS outputs two separate carriers simultaneously with an inter-band hopping time of<1.2 ns.The full chip consumes a maximum current of 420 mA under a 1.2-V supply. This paper presents a first monolithic RF transceiver for DC-OFDM UWB applications. The proposed direct-conversion transceiver integrates all the building blocks including two receiver (Rx) cores, two transmitter (Tx) cores and a dual-carrier frequency synthesizer (DC- FS) as well as a 3-wire serial peripheral interface (SPI) to set the operating status of the transceiver. The ESD-protected chip is fabricated by a TSMC 0.13-μm RF CMOS process with a die size of 4.5 x 3.6 mm ~ 2. The measurement results show that the wideband Rx achieves an NF of 5-6.2 dB, a max gain of 76-84 dB with 64-dB variable gain, an in- / out-of-band IIP3 of-6 / + 4 dBm and an input loss S_ (11) of <-10 in all bands. The Tx achieves an LOLRR / IMGRR of -34 / -33 dBc, a typical OIP3 of +6 dBm and a maximum output power of -5 dBm.The dBm and an input loss S_ DC-FS outputs two separate carriers with an inter-band hopping time of <1.2 ns.The full chip consumes a maximum current of 420 mA under a 1.2-V supply.