Trap rich silicon-on-insulator (TR-SOI) substrates have been widely adopted for high performance RFICs in cellular front-ends over the past few years. With the more stringent loss and harmonic requirements for 4G and even 5G networks, TR-SOI substrate's quality has been improved continuously since its introduction. Two representative types of commercially available TR-SOI substrates are investigated in this paper to demonstrate both small and large signal performance up to 10 GHz. 50 Ohm CPW lines and spiral inductors were fabricated on HR-SOI, TR-SOI, and quartz substrates. The experiment results show that TR-SOI substrates present attenuation coefficient less than 0.2 dB/mm, which is close to that of quartz substrates, and much improved harmonic suppression than HR-SOI substrates.