Sybille Holzwarth

Smart Antenna Terminals for Broadband Mobile Satellite Communications at Ka-Band

This paper deals with a modular Rx- and Tx- antenna terminal featuring digital beamforming (DBF) at Ka-band frequencies. Background and vision of the project SANTANA II and recent realizations are described. Different system components are outlined covering digital baseband, RF- and IF- level as well as software aspects. An outlook on mobile field tests, which will be reported at the conference, concludes this contribution.

A 30 GHz highly integrated LTCC antenna element for digital beam forming arrays

The increasing demand for mobile access to fast data services is one of the drivers for future broadband satellite systems. In-flight data exchange between aircraft and satellites for real-time Internet access is a prominent example for this kind of satellite link. Antennas employing digital beam-forming provide the fast and flexible reconfigurability required in such a system without the necessity for moving mechanical parts. The antenna presented is a circularly polarised, 4/spl times/4 element array building block. This module can be used for a digital beam forming terminal transmitting system operating at 29.75 GHz (Baggen, L. et al., IEEE Phased Array Systems and Technology, p.571-76, 2003). The array features a calibration network as well as transmitting circuitry for each single element. This high density integration task is achieved by the vertical integration of antenna and circuitries in an LTCC multilayer module.

Components of a highly integrated DBF terminal antenna for mobile Ka-band satellite communications

In this paper several components for a highly integrated digital beamforming (DBF) antenna array for Ka-band satellite systems are presented. The general concept of array construction based on a modular approach is introduced and the construction of a constituent array module discussed. Following this outline, different components, designed and tested to later be incorporated into the array module, are treated with the focus set on the Ka-band receiver and transmitter frontends.

Circularly polarised patch over EBG groundplane for galileo applications

This paper presents a novel EBG-backed antenna for geodesic applications using the future Galileo system. The antenna presents a high multipath discrimination and a very stable phase centre. The EBG ground plane proved to be a high performance, low-cost, low-weight alternative to the use of a choke ring.

Innovative Antenna Front Ends from L-Band to Ka-Band [Antenna Applications Corner]

We provide an overview of several high-tech antenna apertures and antenna front ends, developed and realized by IMST (in some cases in cooperation with partners) over a time span of more than 15 years. These front ends have become key components for bandwidth-hungry applications such as mobile/nomadic satellite communication terminals (satcom-onthe-move) and radar systems. Satcom terminal data throughput for multimedia services provided via satellite links is increasing rapidly. Such terminals require highly complex radio-frequency (RF) systems capable of tracking satellites despite movements of the mobile terminal platform. Depending on the type of platform (land mobile, maritime, or aeronautical), the requirements for these front ends and the resulting complexity can vary. This also applies to radar sensors for automotive applications and unmanned aerial vehicle (UAV) platforms, for example. In all of these front ends, the antenna architecture is always based on a phased/steerable array topology. Such systems are, in general, complex configurations: they require not only RF circuitry but also complex baseband processing and highly accurate sensor platforms to perform adequate beam steering and tracking. The overall design must be cost-effective, a very demanding requirement. Through the years, IMST has developed a customized set of highly specialized skills to address all of these challenges.

Circularly polarised digital beam forming transmitting array for mobile satellite communications

The paper presents a circularly polarised digital beam forming (DBF) antenna array. The array consists of 4/spl times/4 elements, and forms a building block for high gain DBF arrays for mobile satellite communications at 30 GHz. After a general introduction, the antenna element and interconnect design are discussed. Subsequently, the transmitter architecture is introduced to illustrate the complexity of the whole system. Finally, measurements of the electronically steered array are presented.