Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q21/00—Antenna arrays or systems
  • H01Q21/0087—Apparatus or processes specially adapted for manufacturing antenna arrays
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q21/00—Antenna arrays or systems
  • H01Q21/0006—Particular feeding systems
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q21/00—Antenna arrays or systems
  • H01Q21/06—Arrays of individually energised antenna units similarly polarised and spaced apart
  • H01Q21/061—Two dimensional planar arrays
  • H01Q21/065—Patch antenna array

Definitions

• the present invention relates to microwave communication and further relates to a design of a beam-forming network.
• Dual Polarized antenna on microstrip patch radiator is fed with multilevel high power hybrid beam forming network (BFN).
• BFN is heart of such an antenna system as it not only provides the requisite excitation for required radiation but also brings down the high power level to a level, which can be tolerated by microstrip feed line.
• the key requirements for the BFN are wide band operation, highly precision power division (typically 0.5 dB in amplitude and 5.0° in phase), high power capability and reliable technology for air-borne and space-borne applications.
• a need for power distribution network capable operating in a high power and also compact is required.
• a development of a new type of multilevel corporate power distribution network capable of coupling power efficiently from a wave guide to primary square coaxial network then to secondary square coaxial network and finally from square coaxial to microstrip network.
• This power distribution network finds its extensive application in beam forming networks where high power operation is required especially in SAR applications.
• the beam forming network is a combination of waveguide, square coaxial line and microstrip line to cater high power requirement. Shaping is provided by developing new pattern synthesis technique for getting ripple free pattern with optimized current taper ratio and mutual coupling making it feasible for realization.
• the invention has led to the development of a unique power distribution network combination of waveguide and square coaxial line making it feasible for multilayer printed microstrip antenna as viable radiating element option for high power airborne SAR applications. This will facilitate enhanced bandwidth, low insertion loss with improved cross polarization.
• a Beam forming network made of hollow waveguide is best suited from the point of view of power handling but from the weight and compactness point of view, BFN are not generally made solely of waveguides.
• rectangular (or more specifically square) coaxial lines are used as transmission medium at the lower frequency range like L-band, C-band up to X-band.
• Circular coaxial lines have been used extensively in the past does not provide (a) the presence of flat surface for mechanical advantages, and to have an unambiguously defined plane of polarization. Moreover it may be conjectured that in practice, at least in some instances the cross polarization ratio, or ability to discriminate against waves having the undesired alternative polarization, may be superior for rectangular lines.
• This invention describes various transitions such as square coaxial transition to microstrip by designing probe with linear taper to match the impedance and grove discontinuity in inner conductor is provided to match the reactance.
• New square coaxial line transition is developed by providing groves in both inner & outer conductor for broadband matching and making it feasible to operate at higher frequency up to X band.
• the power from wave-guide to square coaxial line is transferred by developing top loaded probe. Power is also efficiently coupled to driven printed patch and then to parasitic patch radiator for offering wide bandwidth.
• the invention relates a hybrid beam forming network having a multilevel power distribution network for high power antenna system
• the input guide providing input to a perpendicular guide
• both the guides being connected by means of LMP soldering
• a square coaxial to square coaxial line transition unit capable of connecting between two different layers of a feeder network by means of a circular coaxial line
• the said unit having a discontinuous groove in the inner conductor to optimize with respect to the outer conductor
• the transition unit having a output guide being HMP soldered to a curved perpendicular guide extended firm the waveguide
• a square coaxial to microstrip transition unit with a discontinuous groove in the inner conductor to enable it work with the different frequencies and a microstrip feed network for complex excitation at multilayer printed antenna optimized by generating pair of the roots that lie off the unit circle.
• a dual polarized shaped beam antenna with a multilayer printed antenna comprising a first Layer having a C-flange Clamp, a T-flange Clamp and a plain flange placed at a defined distance away from each other, a second layer to provide the input through two waveguides WRl 59, a third layer having a covering plate for housing 1 x 4 to support the 1 x 4 waveguide in the next layer, a fourth layer 1 x 4 left inner conductor and 1 x 4 right inner conductor, both the conductors distributing 1 input to 4 outputs, comprising a rectangular waveguide to square coaxial unit at the input end and a square coaxial to a square coaxial transition units connecting to the next layer at the output end, a fifth layer having two housings for 1 x 32 square coaxial line by providing a four asymmetric 1 x 8 sections with two on each sides asymmetric to next pair; a sixth layer forming a coverplate bottom for the 1 x 64 housing formed from
• Fig 1 describes a three dimensional view of dual polarized antenna with multilevel hybrid beam forming network.
• Fig 2 shows the detail of the hardware.
• Fig 3 describes input section of rectangular waveguide WRl 59.
• Fig 4 shows the details of 1x16 square coaxial feed network for dual polarization
• Fig 5 shows the details of 1x4 square coaxial feed network for dual polarization
• Fig 6 shows inner conductor of 1x4 square coaxial line and various transitions.
• Fig 7 shows inner conductor of 1x8 square coaxial line and various transitions.
• Fig 8 shows different parts of 1x8 square coaxial line.
• Fig 9 shows square coaxial line to microstrip line transition and square coaxial line to square coaxial line transition.
• Fig 10 shows 8x32 element microstrip feed network layer and patch layer of the dual polarized antenna.
• a 3D view of a dual polarized antenna with multilevel hybrid beam forming network is described, this is further defined in a exploded view of the antenna.
• a dual polarized shaped beam antenna with a multilayer printed antenna (Fig 2)is formed by layers. It has a first Layer having a C-flange Clamp (Ia), a T- flange Clamp (Ib) and a plain flange (Ic) placed at a defined distance away from each other.
• the second layer provides the input through two waveguides WRl 59 (2a, 2b), which is later distributed through the network.
• a detailed view of the waveguide is given in fig 3.
• the third layer has a covering plate for housing 1 x 4 (3 a) to support the 1 x 4 waveguide in the next layer the housing unit is defined in fig 5 which shows a top housing which forms the layer.
• the fourth layer has a 1 x 4 left inner conductor (4a) and 1 x 4 right inner conductor (4b), both the conductors distributing 1 input to 4 outputs (fig 7), this layer has a rectangular waveguide to square coaxial unit at the input end and a square coaxial to a square coaxial transition units connecting to the next layer at the output end.
• the fifth layer has two housings for 1 x 32 (5a ,5b and fig 5) square coaxial line. It is provided by a four 1 x 8 sections with two on each sides.
• the section pair is asymmetric to next pair opposite to each other, thus forming a 32 output.
• the sixth layer forms a coverplate bottom (6) for the 1 x 64 housing formed that is formed from the fifth layer.
• the last three layers form a microstrip feed network patch layer (Fig 11) that comprises a feed network microstrip line (7), a lower patch layer (8), a Rohacell foam layer (9), and an upper patch layer (10)
• a hybrid beam forming network having a multilevel power distribution network for high power antenna system comprising comprises the following transition units
• This transition will couple power from waveguide to square coaxial line.
• Dominant mode in rectangular wave guide is TElO while in square coaxial line it is TEM mode. Mode conversion has been carried out by top loading probe to give required capacitive component. A dumb bell shaped probe is used to couple the power.
• This transition is shown in sheet 6.
• the rectangular waveguide to a square coaxial line transition unit has a input guide (4c) providing input to a perpendicular guide (4d), both the guide being connected by means of LMP soldering.
• This transition will connect two different layers of the feeder network in square coaxial line (SCL).
• a circular coaxial line is used for connecting the the two layers.
• the performance of the return loss as well as insertion loss is achieved by optimising the groove discontinuity of inner conductor as well as location of the end of inner conductor with respect to outer conductor.
• the schematic view is given in sheet 9.
• the square coaxial to square coaxial line transition unit is capable of connecting between two different layers of a feeder network by means of a circular coaxial line, the said unit having a discontinuous groove in the inner conductor to optimize with respect to the outer conductor or broadband matching, the transition unit having a output guide (4b) being HMP soldered to a curved perpendicular guide extended from the waveguide;
• Square Coaxial Line to Microstrip line Transition Transition from square coaxial line to microstrip line is most critical for required impedance matching.
• a single transition does not work for all the frequency ranges.
• To achieve good return loss and power coupling shape of the square coaxial line is modified at the location of the transition by providing a groove discontinuity. These different discontinuity in the inner conductor shape leads to working of the transition in different frequency range.
• This transition is shown in sheet 9.
• a square coaxial to microstrip transition unit having a probe with linear taper to match the impedance and discontinuous groove in inner conductor is provided to match the reactance and enable it to work with the different frequencies.
• This feeder network has been designed to achieve required amplitude and phase computed from null perturbation technique. Optimization has been carried out by generating pair of the roots for all the root that lie off the unit circle.
• the feeder network is of corporate type resulting in less phase dispersion and therefore provides large bandwidth 5.0%.
• This feeder network is shown in sheet 10. Microstrip feed network for complex excitation at multilayer printed antenna optimized by generating pair of the roots that lie off the unit circle.
• the antenna uses high power multilevel waveguide to square coaxial line, square coaxial line to microstrip using hybrid power distribution network.
• Hybrid high power distribution network for dual polarization operation consists of H-plane power divider, Square coaxial corporate line feed network and microstrip corporate type of feed network.
• Step distribution is given in square coaxial corporate feed network to get required suppressed side lobe level.
• Complex current excitation at eight input ports of microstrip patch antenna is achieved by microstrip power distribution network.
• Multilayer EMCP radiator has been selected for required wide bandwidth, low cross polarization and low insertion loss.
• the high power hybrid power distribution network can be used as a beam forming network for high power antenna systems used in airborne and space borne applications.

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• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Waveguide Aerials (AREA)
• Variable-Direction Aerials And Aerial Arrays (AREA)

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• 2009
  • 2009-01-01 CN CN2009801073435A patent/CN102037610B/zh not_active Expired - Fee Related
  • 2009-01-01 EP EP20090708917 patent/EP2243195A4/en not_active Withdrawn
  • 2009-01-01 WO PCT/IN2009/000001 patent/WO2009098713A2/en active Application Filing

Non-Patent Citations (2)

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