Produce Power Efficiently—at High Frequencies, High Voltages and with Short Switching Times

Components for digitization in mobile communication, for industrial and biomedical systems as well as for use in space.

The Ferdinand Braun Institute, Leibniz Institute for High Frequency Technology (FBH) at the EuMW in Paris presents a selection of current further and new developments of its power amplifiers, circuits and heterointegrated chips. From September 29 to October 4, 2019, FBH will be present at the conference and will be presenting itself at the accompanying trade fair at joint booth B2200 of the "Forschungsfabrik Mikroelektronik Deutschland" from October 1-3.

In addition to its components for 5G, the communication in space and terahertz systems for imaging techniques, the FBH also shows a live demonstrator for pulsed laser sources. With a fast-switching GaN-based driver, the pulse duration and intensity can be flexibly adjusted from 200 ps to 20 ns. The system can be flexibly equipped with laser diodes of various wavelengths (630 - 1180 nm). In LiDAR systems, for example, wavelength-stabilized laser diodes are used at 905 nm with 100 watts output power and pulse widths of 3-10 ns.

Components for 5G and for satellite communication and sensor technology

Around 5% of global energy use is attributed to the use of information and communication technologies—in the telecommunications sector alone, demand is increasing by 10% annually. The planned 5G systems use higher frequencies, thereby enabling greater signal bandwidth. The FBH presents two approaches to improve their energy efficiency: a fully digital transmitter architecture and supply voltage modulation for linear amplifiers.

For mobile communications of the future, the institute is developing digital power amplifiers with efficient amplifier chips based on FBH's 0.25 μm GaN HEMT process. With them, the institute has realized the first fully digital transmitter chain that successfully transmits broadband signals with maximum efficiency and linearity (47% at >52 dB ACLR). The compact digital transmitter is particularly suitable for multi-antenna systems (Massive MIMO), where it is mounted on the back of the antenna.

As a second approach, systems are implemented whose supply voltage is modulated and which are suitable for 5G and satellite communications. They very efficiently amplify signals with extreme modulation bandwidths. For example, FBH and the European Space Agency ESA have developed a novel Envelope Tracking (ET) communicator in space at 1.62 GHz. The amplifier has a peak output power of more than 90 W with a modulation bandwidth of 40 MHz. With an 8.6 PAPR signal, the overall efficiency is 40%.

Concepts with modulated supply voltage are now also being transferred to millimeter-wave amplifiers, which is of interest for 5G base stations. The FBH has developed a corresponding module consisting of two identical MMICs connected in series. These each consist of a single-stage amplifier with integrated two-stage voltage switch (class G). The module operates in the range of 20 - 26 GHz with 14 dB gain and more than 2 W/mm at 20 V supply voltage.

For satellite sensor technology, FBH is also developing a modular MIMO radar at 85-95 GHz based on FBH's InP transfer substrate DHBT process. The imaging radar will in future locate and track objects in the vicinity of satellites. For this purpose, a complete chipset was developed and integrated into a module. The chipset uses novel MMICs with a high output power of >15 dBm, a low noise figure NF

Terahertz detectors and arrays for imaging systems

The terahertz (THz) range provides good spatial resolution and can penetrate most non-metallic materials. This makes it suitable for a wide range of industrial and safety-relevant applications. However, there are still no imaging systems with sufficiently high sensitivity and readout speed in this frequency range. Among other things, there was a lack of sensitive, fast and cost-effective THz detectors that can be upgraded to THz cameras. The FBH has successfully developed such detectors, which can also be arranged in arrays. The III / V-based THz detectors offer best equivalent NEP 100 mA/W at 500 GHz. These values ​​surpass the best THz detectors in CMOS technology. It is now planned.