The S-band Transmitter from ISISPACE is a Space Transmitter with a transmitter frequency range of 2200-2290 MHz and an RF output power of 27-31 dBm. This S-band transmitter supports BPSK and OQPSK modulation schemes and has a transmitter data rate of up to 10 Mbit/s. It has a frequency stability of +/- 0.28 ppm and a frequency step size of 1 kHz. The transmitter module supports LVDS and I2C interfaces. It requires a DC supply voltage of 7-20 V and has a power consumption of 13 W. The transmitter has a mass of 132 g and measures 98.8 x 93.3 x 14.5 mm. It is suitable for applications of CubeSat TT&C and CubeSat RF payloads.