Site: Daimler Chrysler Research Center Ulm
Wilhelm-Runge Str. 11
89081 Ulm (Donau)
Date Visited: 27 April 1999
WTEC Attendees: L. Katehi (report author), T. Itoh, D. Friday, R. Pickholtz
Hosts: Johann-Friederich Luy
The Ulm research facility has a total of 450 researchers and support personnel and is situated 3 km outside Ulm. The whole lab occupies 23,000 sq. ft of clean space including clean facilities from 10,000, to 1, as show in Fig. C.1.
Fig. C.1. Daimler-Chrysler Research Center, Ulm.
The Daimler Chrysler research labs were reorganized recently. The company follows an R&D 3-vector model in which technological competence, customers, and research programs constitute the three axes of a multi-dimensional research space. The research activities in the Daimler Chrysler Research Center in Ulm cover five core technology fields:
Among the applications that can possibly be covered under these technology areas, emphasis is given to the following:
In each of these areas, Daimler Chrysler and DASA are developing products that address a number of customer needs as shown in Fig. C.2. The wireless communications applications and customer products cover a wide range of high frequencies from 800 MHz to 77 GHz and require high operation speeds from a fraction of a Gbps to tens of Gbps. Research efforts in these application areas include development of software radio, digital receivers, micro-millimeter wave mobile communications and radar systems, contactless sensors, and antenna technology for digital beam-forming for high density TV. In high frequency device development, the company is focusing on the development of III-V based 2.5 GHz and 5 GHz mobile phones. However a serious effort is being undertaken to develop SiGe based devices to accomplish high density and multi-functionality.
Fig. C.2. Technical trends to meet future society demands.
The strength of this center is the development of high-frequency device, circuit and antenna design for the above described communication systems. The research groups have demonstrated world records in InP HEMTS technology (see Fig. C.3).
In addition to InP, Daimler-Chrysler has seriously invested in GaN technology and has demonstrated microwave high power modules with fmax above 50 GHz. Effort is presently underway to incorporate this technology into imaging radars operating at millimeter-wave frequencies.
Fig. C.3. Overview of Daimler-Benz InP-based HEMTs.
To achieve high integration and multifunction capability, Daimler Chrysler is pursuing the development of SiGe-Si microwave and millimeter wave integrated circuits (SiGeSIMMWIC) for range sensors, speed control, etc. In addition to integration and performance, the company expects low cost to be the driver in using this technology in customer products for wireless applications. Such applications include communications and sensing/navigation. Comparisons made between InP-, GaN-, and SiGe-based products show superior cost potential in the SiGe technology (see Fig. 5.11, p. 40) and indicate device superiority due to very low 1/f noise and low phase noise: SiGe transit-time diodes in self-oscillating mixers have demonstrated frequency stability with sub-harmonic locking. Free running has demonstrated about -60 dBc/Hz at 100 kHz from the carrier and with phase locking about -90 dBc/Hz at 100 kHz from the carrier. In this circuit technology, CPW has been chosen as the interconnect medium due to its superiority to thin film microstrip and its associated need of a via hole technology. CPW solves a number of problems but requires an air-bridge technology, which however is easier to make due to its requirements of wafer-surface and not wafer-bulk fabrication.
Daimler Chrysler is the leader in SiGe technology and has demonstrated performance records in SiGe HBT as shown in Fig. 5.12 (p. 40). A number of SiGe applications include Ka-Band CPW oscillator HBTs, a 77 GHz near-field sensor with SiGe Schottky diodes, and a 77 GHz closing velocity sensor. While SiGe technology is progressing fast, a number of processing issues still need to be resolved. To alleviate some of these issues, passivation of the device by a Si3N4 has been adopted. Low temperature, low power cpw-based HBT structures are routinely demonstrated (20 mW at 47 GHz) (6 emitter figure device). At present, research is focused on the development of phase resonant devices with fmax=300 GHz achieved by quantum-well injection.
Daimler Chrysler is inserting this technology into customer products via an extensive product development effort performed in the "Microwave Factory" owned by DASA. This facility called the "M5-Service Center" (Microwave and Millimeter-Wave Module Engineering and Manufacturing Services) enables the development of products based on the research of the various D-C research centers. This center has 84 staff members, occupies 10,000 sq. ft. of dedicated space, and has a DM 17 million measurement facility in addition to the fabrication facilities. Sensors such as SatCom, MobilCom, Cruise control at 77 GHz, and LMDS at 28 GHz, as well as a 24 GHz radar designed to measure material properties for application in steel production, have been produced. Other products include a 58 GHz point-to-point link in hybrid formulation with GaAs MMICs using bonding wires for connection to MMIC chips. This facility has been sole supplier to many communications companies (including Nokia) and focuses on defense/space products for guidance and communications, with 60-70% in defense and 30-40% in commercial communications. The antenna group of DASA does all antenna measurements.
In communications technology, Daimler Chrysler is investing in telematics, advanced media and services, information technology, and software technology. Efforts are focused on application specific solutions for a variety of services including vehicle IT systems, personalized security systems, vehicle integration antennas, vehicle networks, multi-agent systems, and object oriented techniques. Other applications include the following:
In addition to the above, Daimler Chrysler is developing optical back planes for board-to-board interconnection. The back planes interconnect high-performance signal processors for modular avionics that require 1-8 Gbps and require serial buses instead of parallel busses. The backplanes are designed in ring or star configurations. Back planes offer advantages over space transmission since they provide a vibration-free solution. Free-space transmission and optical guidance through a polymer wave-guide give a 3 dB loss with an axial tolerance > 2mm and lateral tolerance better than ± 500 micros. Power budgets are very critical, and wave guide attenuation better than a few dB/m is required to make designs successful. Polymer optical wave-guides with 1-3 dB/m attenuation in the short wave are used and are coupled through mirrors for good efficiency and low spillover. This technology has been demonstrated in a 1 Gb application. The length of the back plane was 26 cm and exhibited 3.5 dB loss. Demonstrated system margin was approximately 10 dB. Planar optical wave-guide crossing loss =0.7 dB, and line loss can be improved by anti-reflection coating. Total loss can be as low as 2.5 dB. An issue that needs to be addressed is the collection of particles on the transitions of the optical wave-guide or on the lenses. Vibration tests have shown excellent potential and aging tests of the low-loss wave-guide (200 hours) have indicated no increase in losses. Possible applications may provide 2.5 Gbps, while interconnection lengths up to 19 inches have been achieved.