This paper presents and compares the design and measurement results of two D-Band MIMO radar IC versions regarding their transmit paths in Infineon's $0.13\ \mu \mathrm{m}$ SiGe BiCMOS technology B11HFC. Each MMIC is mounted on a testing PCB where a differential feeding structure is connected to a D-Band rectangular waveguide (RWG). Every MMIC has four transmit paths, which generate and drive the D-Band signals, and four receive paths. These signals result from frequency multiplication with octuplers that consist of bootstrapped frequency doublers, distribution networks, filters, and PAs. Due to minor changes to components at the beginning of the octupler chain, the second MMIC achieves a better spectral purity of the output signal. At the center frequency, the harmonic rejection increased by more than 13 dB with respect to unwanted frequency components in the D-Band. Overall, both versions have a measured 3 dB bandwidth of 37 GHz/31 GHz with a peak output power of −7.4 dBm/−4.7 dBm and a center frequency of 132.5 GHz/134.5 GHz.