Electronic Beam Scanning For Radar Applications Nizam ud Din ,Asad Afzaal, Junaid Tahir, Nasir Hafeez Depa rtment of Electrical Engineering National University of Computer and Emerging Sciences (FAST-NUCES) Islamabad, Pakistan
[email protected], asad
[email protected], juna id.ta hir@ya h oo .co m, nasir 5 00@h o tma il .co m
Abstract-The design of a passive phased array transmitting antenna is proposed. The antenna uses spatial spacing of the array elements for phase shifting. The antenna operates at a frequency of 2.42 GHz (in the 2.4 - 2.5 GHz range of ISM Band). The antenna provides a gain of 8.31 dB and the radiating power is 33.7 dBm with an efficiency of 97.7%. Beam steering is performed by feeding the array using a fixed frequency and variable phase angles. The one-dimensional, series-fed array has a beam steering capability of about 60°. The antenna is useful for radar, S-Band satellite communication and short range wireless
(HFSS). We were successful in designing a phased array antenna and demonstrating beam steering. The first objective was to design a single patch antenna then a working phased array antenna by choosing an appropriate feeding network. Our final goal was to implement beam steering i.e. electrically changing the direction of the main lobe of the radiation pattern by changing relative phases of the signal being fed to the antenna elements. II.
and mobile applications.
Keywords- Phased Array Antenna; Beam Steering; ISM band; Series Array; Radar Communication; Beam Scanning. I.
PATCH ANTENNA DESIGN
We started designing a rectangular patch antenna with series feed. A generic rectangular patch antenna with series feed is shown below in Fig. 1 [3]:
INTRODUCTION
A phased array is a group of antennas in which the relative phases of the respective signals feeding the antennas are varied
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in such a way that effective radiation pattern of the array i s reinforced i n a desired direction and suppressed i n undesired directions. Phased array antennas are an extremely interesting
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area of study with numerous applications in diverse areas like broadcasting, optics, defense, weather research, communication, radio frequency identification, etc.
satellite
Beam steering has been one of the most important requirements in relation to antennas in satellite and wireles s applications. Microstrip antennas are the ultimate choice when it comes to low profile, low cost, low weight, reliable and easily fabricated antennas. A rectangular patch antenna is the most popular choice among other geometries. Most often different types of current feeding schemes and active components are required for controlling the phase of current driving each array element. In set ups where a dedicated signal generator is provided there is no need of deploying active components within the array. The proposed work investigates the chance of achieving good scanning under these set ups. This paper suggests a simple array fed from a single source giving a return loss below lOdB. After studying several
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