Linear power and efficiency at microwave and millimeter-wave using twta based microwave power modules [Application notes]

The results in this article clearly indicate the importance of millimeter-wave power module (MPM) technology and illustrate the enormous value of combining an MPM with a linearizer. This combination makes linearized MPMs highly attractive for commercial and government communications applications. A linearized-MPM can provide significantly higher power and efficiency for a comparable linearity in a lighter weight and more compact package than alternate options. The linearizer allows an MPM to provide four times the output power for many linear applications, and more than a 10 dB improvement in two-carrier linearity over much of its power range. For currently available MPMs, linearization allows operation with common digital modulations with a spectral regrowth of greater than 30 dB at an output power of 50 W with an overall efficiency of 25%. Even greater benefits are provided for complex digitally modulated signals as wideband code division multiple access (WCDMA). This MPM can be housed in an 820 cubic cm volume, 2.3 kg in weight and allows operation over multi-octave bandwidths.

Microwave Power Modules

MPMs have been developed for operation from below 2 GHz to over 45 GHz, and work is in progress to extend this range to above 80 GHz. Wideband MPMs are available that operate at 2–8 GHz, 4.5–18 GHz, and 18–40 GHz with RF output power levels of up to 250 W, noise figures of less than 10 dB, and an efficiency up to 60% [7]. MPMs are used for military applications, including unmanned aerial vehicles (DAVs), decoys, radar and phased array systems. MPMs are designed to be modular and can be reconfigured for a variety of form factors and formats to meet changing systems needs. Figure 2 shows some of the forms in which MPMs can be found. MPMs are available from a number of traveling wave tube manufacturers including CPI, L-3 Communications Electron Devices, NEC, Northrop Grumman and Thales. Figure 2.

Microwave power modules are found in a variety of forms, and can be less than 800 cm3 in volume and 2.25 kg in mass (from [3]).