Wideband traveling wave PIN Diode switches and attenuators are proposed. The switches and attenuators consist of three shunt PIN diodes, six radial stubs, bias circuit and DC return circuit. Wide bandwidth is achieved with six different radial stubs as reflective load of the diodes. The stubs work as short circuit to the diodes at different frequency points for broad bandwidth. For the Single pole single throw (SPST) switch, the lowest measured Insertion loss (IL) is 0.75dB and lower than 2.0dB in 85–105GHz, and its isolation is better than 21.3dB. As a Voltage-controlled variable attenuator (VCA), typical attenuation range is 23dB and attenuation fluctuation is lower than 5dB in 85–105GHz.