X-band active transmit phased array for satellite applications

Zaghloul, Amir I.; Sichan, L.; Upshur, J.I.; Estep, G.; Gupta, Rakesh Kumar

doi:10.1109/past.1996.566098

Cited by 4 publications

(4 citation statements)

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“…A study performed at COMSAT Laboratories addressed a set of requirements for a future DSCS system (Zaghloul, 1996). A key antenna specification is to transmit four beams simultaneously.…”

Section: X-band High-power Active Phased Arraymentioning

confidence: 99%

“…A number of advanced concepts employing active phased arrays have been investigated. Among the early developments are Ku-band and X-band arrays that were sponsored by INTELSAT, COMSAT Corporation and the US Air Force , (Zaghloul, 1996). Another array was also developed at COMSAT Laboratories at C-band to produce eight simultaneous and independently shaped and steerable beams.…”

Section: Introductionmentioning

confidence: 99%

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System Aspects of Active Phased Arrays

Zaghloul¹,

Kıłıc²,

C.³

2010

Satellite Communications

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“…A study performed at COMSAT Laboratories addressed a set of requirements for a future DSCS system (Zaghloul, 1996). A key antenna specification is to transmit four beams simultaneously.…”

Section: X-band High-power Active Phased Arraymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

System Aspects of Active Phased Arrays

Zaghloul¹,

Kıłıc²,

C.³

2010

Satellite Communications

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“…The subarray consists of eight elemcnts in two rows composed of four scalar ring horns each [2]. The elements are arranged in a triangular lattice with the horns tangent to each other.…”

Section: X-band Multiple-beam Active Phased Arraymentioning

confidence: 99%

“…Another array was developed at C-band to produce eight simultaneous and independently shaped and steerable beams [I]. A third example is an array that was designed at X-band and sponsored by the US Department of Defense as a proof of concept for a four-beam array providing spot coverages over the earth disc for DSCS-type (Defense Satellite Communications System) service [2]. The Ku-band arrays use dual-linearly polarized square horns as the radiating elements, while the C-and X-band arrays use circular polarizations produced by printed circuit radiators and scalar ring honis, respectively.…”

Section: Introductionmentioning

confidence: 99%

Use of active phased arrays for multiple-beam cellular communications systems

Zaghloul

Kıłıc²

Proceedings of the Nineteenth National Radio Science Conference

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Active phased array antennas offer an efficient and more versatile alternative to reflector antennas for use in communications systems that require multiple beams. The use of such antennas is evident in newly developed satellite communications systems and in base stations for wireless systems. In satellite systems, global, regional and zone coverage on the earth surface are traditionally accomplished using multibeam reflector antennas that use a number of feed elements or shaped reflectors that use a single feed per beam. Recent demands for large number of spot beams with high beam-to-beam isolation and the need for flexibility in steering the beams imposed new requirements on the communications system that are easier met with active phased arrays. The advances in Monolithic Microwave Integrated Circuits (MMIC) and digital technologies played a major role in realizing these arrays for satellite applications. However, the added requirements and active array characteristics introduce a set of transmission impairments in the communications link that did not necessarily exist in the conventional systems. This paper reviews phased array developments for multiple-beam cellular communications applications. The paper describes hardware designs to meet coverage requirements. These include the modular MMIC beam-forming matrices that generate a number of simultaneous and independent beams that are controlled digitally. The communications link and system aspects of the active phased array are assessed through measurements and analysis. Three link parameters are investigated and their effects on the overall carrier-to-interference ratio are quantified. The first parameter is the intermodulation components that are generated at the non-linear amplifier outputs and contribute to well-formed interference in the far field radiation of the array. The second is the bit-error ratio (BER) degradation due to the multi-carrier operation of the active array. Measurement results are shown to demonstrate this effect. The third link parameter is the co-channel interference caused by frequency re-use in multiple beam systems. Antenna performance for both user terminals and satellite payload (or cellular system base station) as well as coverage requirements and user traffic within each beam contribute to this interference effect.Introduction:

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