Andreas Fleckenstein

Bio: Andreas Fleckenstein is an academic researcher. The author has contributed to research in topics: Noise figure & Microstrip. The author has an hindex of 4, co-authored 4 publications receiving 107 citations.

GaN MMIC based T/R-Module Front-End for X-Band Applications

Abstract: Amplifiers for a next generation of T/R-modules in future active array antennas are realized as monolithically integrated circuits (MMIC) on the bases of novel AlGaN/GaN HEMT structures. Both, low noise and power amplifiers are designed for X-band frequencies. The MMICs are designed, simulated and fabricated using a novel via-hole microstrip technology. Output power levels of 6.8 W (38 dBm) for the driver amplifier (DA) and 20 W (43 dBm) for the high power amplifier (HPA) are measured. The measured noise figure of the low noise amplifier (LNA) is in the range of 1.5 dB. A T/R-module front-end with mounted GaN MMICs is designed based on a multilayer LTCC technology.

T/R-module technologies today and future trends

Abstract: After many years of development the active electronically scanned array (AESA) radar technology has reached a mature technology level. Many of today's and future radar systems will be equipped with the ASEA technology. T/R-modules are key elements in active phased array antennas for radar and electronic warfare applications. Meanwhile T/R-modules using GaAs MMICs are in mass production with high quantities. Top priority is on continuous improvement of yield figures by optimizing the spread of key performance parameters to come down with cost. To fulfill future demands on power, bandwidth, robustness, weight, multifunctional sensor capability, and overall sensor cost, new emerging semiconductor and packaging technologies have to be implemented for the next generation T/R-modules. Using GaN MMICs as HPAs and also as robust LNAs is a promising approach. Higher integration at the amplitude and phase setting section of the T/R-module is realized with GaAs core chips or even with SiGe multifunction chips. With increasing digital signal processing capability the digital beam forming will get more importance with a high impact on the T/R-modules. For lower production costs but also for sensor integration new packaging concepts are necessary. This includes the transition towards organic packages and using low cost surface-mount soldering technology.

T/R-module technologies today and possible evolutions

Abstract: After many years of development the active electronically scanned array (AESA) radar technology reached a mature technology level. Many of today's and future radar systems will be equipped with the ASEA technology. T/R-modules are key elements in active phased array antennas for radar and electronic warfare applications. Meanwhile T/R-modules using GaAs MMICs are in mass production with high quantities. Top priority is on continuous improvement of yield figures by optimizing the spread of key performance parameters to come down with cost. To fulfill future demands on power, bandwidth, robustness, weight, multifunctional sensor capability, and overall sensor cost, new emerging semiconductor and packaging technologies have to be implemented for the next generation T/R-modules. Using GaN MMICs as HPAs and also as robust LNAs is a promising approach. Higher integration at the amplitude and phase setting section of the T/R-module is realized with GaAs core chips or even with SiGe multifunction chips. With increasing digital signal processing capability the digital beam forming will get more importance with a high impact on the T/R-modules. For lower production costs but also for sensor integration new packaging concepts are necessary. This includes the transition towards organic packages or the transition from brick style T/R-module to a tile T/R-module.

X-band T/R-module front-end based on GaN MMICs

Abstract: Amplifiers for the next generation of T/R modules in future active array antennas are realized as monolithically integrated circuits (MMIC) on the basis of novel AlGaN/GaN (is a chemical material description) high electron mobility transistor (HEMT) structures. Both low-noise and power amplifiers are designed for X-band frequencies. The MMICs are designed, simulated, and fabricated using a novel via-hole microstrip technology. Output power levels of 6.8 W (38 dBm) for the driver amplifier (DA) and 20 W (43 dBm) for the high-power amplifier (HPA) are measured. The measured noise figure of the low-noise amplifier (LNA) is in the range of 1.5 dB. A T/R-module front-end with mounted GaN MMICs is designed based on a multi-layer low-temperature cofired ceramic technology (LTCC).

A Compact X-Band Bi-Directional Phased-Array T/R Chipset in 0.13 $\mu{\hbox {m}}$ CMOS Technology

Abstract: This paper presents an X-band bi-directional T/R chipset in 0.13 m CMOS. The T/R chipset consists of a bi-directional gain amplifier (BDGA), a 5-bit digital step attenuator with two BDGAs for compensating the switch losses, and a 6-bit phase shifter using DPDT switches. The phase and attenuation coverage is 360 with the LSB of 5.625°, and 31 dB with the LSB of 1 dB, respectively. The circuit has a reference state gain of >;3.5 db, and the return losses of >;11 db at 8.5-10.5 GHz. The T/R chipset has a phase shift accuracy with the RMS phase error of ;6.5 dBm and the noise figure is <;7.5 db at 8.5-10 GHz. The chip size is 2.06 × 0.58 mm2 including pads, and the DC power consumption is 154 mW only in the BDGAs. To authors' knowledge, this is the X-band CMOS T/R chipset with the competitive RF performance compared to other device technologies, which has the smallest size and the lowest power consumption to-date.

An X-Band AlGaN/GaN MMIC Receiver Front-End

Abstract: This letter presents an integrated AlGaN/GaN X-band receiver front-end. This is to the authors knowledge the first published results of an integrated AlGaN/GaN MMIC receiver front-end. The receiver uses an integrated SPDT switch to reduce size, weight and cost compared to circulator based transceiver front-ends. The integrated front-end has more than 13 dB of gain and a noise figure of 3.5 dB at 11 GHz.

X-Band GaN Power Amplifier for Future Generation SAR Systems

Abstract: A X-band GaN monolithic microwave integrated circuits (MMIC) High Power Amplifier (HPA) suitable for future generation Synthetic Aperture Radar systems is presented. The HPA delivers 14 W of output power, more than 38% of PAE in the frequency bandwidth from 8.8 to 10.4 GHz. Its linear gain is greater than 25 dB. For the first time an MMIC X-band HPA has been designed by directly measuring the transistor behavior at the current generator plane. In particular, optimum device load-line has been selected according to the chosen performance tradeoffs.

GaN single-chip transceiver frontend MMIC for X-band applications

Abstract: An X-band transceiver frontend monolithic microwave integrated circuit (MMIC) has been successfully developed by using GaN HEMT technology. The MMIC contains a power amplifier (PA) with output power higher than 19 W at 10.5 GHz, a low-noise amplifier (LNA) with a gain of 18.5 dB and noise figure (NF) of 2.3 dB at 10 GHz, and an SPDT switch. The fabricated transceiver MMIC occupying only 3.6 × 3.3 mm2 delivers an output power of 6.3 W. To the authors' knowledge, this is the first GaN single-chip transceiver frontend MMIC in the X-band.

Realisation of microstrip junction circulator using LTCC technology

Abstract: An integrated circulator based on low-temperature cofired ceramics (LTCC) tapes and LTCC compatible ferrite tapes has been developed for the first time and its performance has been verified experimentally. The insertion loss is less than 2 dB and the isolation is better than 25 dB with a centre frequency of 7.45 GHz. These results are in good agreement with simulations and offer a route towards integrated LTCC microwave circulators.