We proposed a measurement method for radiation pattern of the chip planar antenna. For the verification of the measurement method, we developed a 94‐GHz log‐periodic chip planar antenna on a GaAs substrate. To measure the radiation patterns, the 94‐GHz chip planar antenna was connected by three ribbon bonding wires to the CPW‐to‐WR10 transition. From the measurement at 94 GHz, the back‐to‐back transition has a loss of −4.09 dB and the back‐to‐back transition connected by three ribbon bonding wires has a loss of −5.40 dB. The measurement module has an insertion loss of −3.70 dB and a return loss of −15.79 dB. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2368–2371, 2015