In this paper, 10-MHz-to-70-GHz ultra-wideband low-insertion-loss single-pole single-throw (SPST) and single-pole double-throw (SPDT) switches using GaAs PIN Diode MMIC process are described. The series-shunt topology is employed in the switches to enhance the isolation. The measured 3-dB bandwidths of the SPST and SPDT switches are from 10 MHz to 70 GHz. The measured minimum insertion losses of the SPST and SPDT switches are lower than 1 and 1.1 dB, respectively, and the maximum isolations are both higher than 60 dB. When the input frequency is 2 GHz, the measured input 1-dB compression points of the SPST and SPDT switches are higher than 23 and 25.5 dBm, respectively. The presented switches feature compact chip area, low insertion loss, high isolation, and good power handling, and they are suitable for broadband transceiver applications.