The operation of microwave modulators utilizing 4H-SiC p(+)-i-n(+) diodes and operating in the frequency range of 1 divided by 10 GHz has been simulated. Modulator prototypes with microstrip design have been fabricated on the basis of simulation results. For 4H-SiC diodes used in these modulators the n-region thickness and donor concentration were 2 mum and 1.1(.)10(17) cm(-3), respectively. Diode chips with mesa diameters of 60 divided by 80 mum were used in modulators, and they were mounted into microwave cermet packages to measure microwave parameters. The modulators revealed transmission and isolation losses of -1 and -16 dB at operating frequency of 3 GHz. These experimentally obtained modulator characteristics were in excellent agreement with theoretical values given by simulation.