A high-bandwidth communication modem such as an ultra wideband (UWB) communication modem or a high-giga wideband (HGWB) modem includes an interface configured to transceive data in connection with a host device, a baseband processor configured to process, in a parallel manner, a baseband signal being transceived between the interface and a parallel/serial converter, the parallel/serial converter configured to combine a parallel signal into a serial signal and output the serial signal, and separate a serial signal into a parallel signal and output the parallel signal, a radio frequency (RF) processor configured to reduce a frequency of a received UWB or HGWB signal and transmit the frequency-reduced signal to the parallel/serial converter, and increase a frequency of the serial signal received from the parallel/serial converter and transmit the frequency-increased signal to a directional antenna, and the directional antenna configured to transceive a wireless signal by forming a directional beam and control a direction of the directional beam.