MULTI-ELEMENT PHASED ANTENNA ARRAYS FOR GROUND AND AIRBORNE APPLICATIONS
Michael Parnes - Ascor Co., St.Petersburg ascor@parnes.spb.ru
http://www.ascor.eltech.ru
 
Raphael Shifman - Resonans Co, St.Petersburg shifman@resonance.spb.ru
Tel/Fax No: (7-812) 553-8445
 
 
 
Abstract
 
This paper discusses problems of economical and technological expediency evaluation  in  application  of     electronically  scanned  phased  arrays  for different applications
 

In order to receive a signal from a few satellites, it is customary to use an electromechanically scanned parabolic antenna that has many disadvantages, among them those connected with its poor environmental resistance. A planar antenna is, contrastingly, more resistant to environmental influences such as wind, rain, snow, etc. In addition, it can easier be mounted at the top of building. Therefore, it has since 1986 been suggested that an in-phase planar array[1] antenna containing no phase shifters be used for this purpose (Fig.1).

Fig.1
 
The Matsushita Co. (Japan) has been among leading developers/sellers of such antennas for application to DBS television since 1987. In April 1987 their phased arrays have been purchased for the broadcast reception through the BSB satellite in the United Kingdom and then - for the TV SAT in Germany.
 
The phased array technology itself allows several controlled phase shifters to be installed at the same time as radiators, i.e. solder-mounted on the same printed-circuit board, which increases the cost of antenna, though. For this reason, it is of vital importance for a mass user, as opposed to a military one, to assess wherein lies a novel phased array functionality and what is the price for that complication.

 It can be seen from the analysis that the phased array containing 12 phase shifters may commercially be of interest since it makes possible reception of TV broadcasting within the angular coverage 8° in Western Europe. This sector, in particular, covers the area from ASTRA 1A-1B (19,2° East) to TELECOM 1C (3° East) (Fig.2).
 

Fig. 2
 

Table 1. gives comparison of different phased array versions.

 Table 1
 
Number of 
Phase Shifters
Angular Coverage, 
+/- deg.
Gain, dB 
(normally to 
the surface)
Gain, dB 
(at the edge of 
sector)
Frequency, 
GHz
12
8
34.5
32
10.9-11.7
12
8
35.5
33
11.7-12.75
24
16
33.5
31
10.9-11.7
24
16
34.5
32
11.7-12.75
48
60
34.5
30
10.9-11.7
 
A phased array containing 24 phase shifters is also a promising option covering the sector +/- 16° , e.g. from EUTELSAT 2-F1 (13° East) to TVSAT 2 (19° West). Such a phased array antenna can carry out reception from nine DBSs in the territory of Western Europe.
 
To phase the beam, p-i-n diode phase shifters should be mounted on the 65 x 3 cm printed-circuit board(Fig.3).
 
 Fig. 3

The p-i-n diode phase shifter is controllable through a three-digit code and best compatible with the in-tuner available digital control unit. An essential difference of the planar phased array from the electromechanically scanned parabola is its very short beam switching time, a few microseconds in duration. Such a high beam transport velocity permits the use of the phased array in vehicle based DBS systems (airborne, shipborne, automotive, etc.).

Described technology can be used for other ground based and airborne applications where we need signal reception from different directions. Together with LNA-s this technology can be used for warning collision radars, ground and satellite communications in frequency range from 1-80 GHz. Typical measured power radiation pattern (RP) of our multi-element microstrip array at 37 GHz (Fig 4a) is shown in Fig. 4b.
 

(a)
(b)
Fig. 4
 
We used elements of this technology for multi-element focal MMIC array at 26-30 GHz for RATAN-600 radio telescope [2].

Conclusion

  • The DBS television development analysis indicates that the number of satellites will be growing year after year, just generating a need for reception
  • of signals from different directions using the same antenna. The phased array antenna that uses a printed-circuit board as a radiating curtain and p-i-n diode based microstrip phase shifters appear to have considerable promise for meeting the challenge. A phase shifter of that sort is fully compatible with the tuner processor and will be cost-effective in mass production.
  • The phased array use will permit user-friendly modes of operation, such as automatic search of satellites followed by memorizing their coordinates in order to switch over to the desired satellite within microseconds.
  • The phased array antenna is characterized by its inherent high speed of beam switching and this enables one to use it in DBS systems to be installed on movable objects such as coaches, trucks and ships.
  • Described technology can be used for different ground based and airborne applications as well.
    •      References

    1. M.D.Parnes.Experience of the Automated designing of patch antenna arrays. Ship-building industry(USSR), issue 19, 1989.

    2. V.Khaikin, E.Majorova,R.Shifman, M.Parnes, V.Dobrov, V.Guzevich. MMIC Solution for Multi-pixel Reception in RATAN-600 Aberrational Focal Zone. Proceed. of 2-nd ESA Workshop on Millimetre Wave Technology and Applications, Espoo, Finland, 1998.