Multi-Beam Base Station Antenna · PDF fileDual Band Interleaved Base Station Phased Array...

1PRIVATE AND CONFIDENTIAL. Copyright © 2014 CommScope, Inc. – All rights reserved.

Igor Timofeev

November 2014

[email protected]

Multi-Beam Base Station Antenna Systems

0 10

20

30

40

5060

7080

9010

011

012

013

0

140

150

160

170

180

-170-1

60-150

-140

-130

-120

-110

-100

-90

-80

-70

-60

-50

-40

-30 -2

0 -10

-40

-35

-30

-25

-20

-15

-10-50

mailto:[email protected]


Agenda

Introduction: Multi-beam antennas in wireless communications.

Part 1: Butler Matrix Base Station Antennas

• Review of BFNs: classic Butler matrix, modified Butler matrix, Blass Matrix, Rotman lens.

• Examples of Commscope multi-beam antennas (2-, 3-, 18-beams, 2-band 2-beam).

• Methods of bandwidth increasing for Butler matrix multi-beam antenna arrays.

Part 2: Lensed Multi-Beam BSA

• Review of lensed multi-beam antennas (Luneberg and homogeneous lenses).

• 3-beam lensed BSA.

• Bandwidth increasing for lensed multi-beam antennas.

• Comparison of Butler matrix and lensed solutions


Multi-Beam BSA to Boost Capacity

• More capacity due to increased sectorization

• Could be horizontal and vertical sectorization

• Ideal solution for high traffic sectors and events

• Opportunity: switch beam to provide the best signal for the user (smart antenna)

• Opportunity for coverage sculpting

• MIMO; massive MIMO

2 Beams(2 x 38°)

5 Beams(5 x 12°)

9 Beams(9 x 6°)

18 Beams(2 x 9 x 6°)

3 Beams(3 x 24°)

HBXX-3817TB1-VTM 3-H24A-3XR 5NPX1006F5UPX0805F

2x9NPA2010F 2x9NPA2010F


Part 1: Butler Matrix BSA Arrays

5x5 Blass matrix, 1960

8x8 Butler matrix, 1961

2x3 Butler-style matrix, 2005

2x4 Butler-stylematrix, 2005

16x20 Rotman,lens, 1963

Examples of Beam-Forming Networks

6x6 Butler style matrix,

2005

Directional coupler

Boresight beam

3dB Hybrid


HBXX-3817TB1-VTM Twin Beam Antenna

-180-170

-160-150

-140-130

-120-110

-100-90

-80-70

-60-50

-40-30

-20-10

010

2030

4050

6070

8090

100110

120130

140150

160170

180

-40.00

-35.00

-30.00

-25.00

-20.00

-15.00

-10.00

-5.00

0.00

Measured Az patterns@ 1.7 - 2.2GHz

SLL <-20dB

2x3 Butler matrix 2x4 Butler matrix Phase shifter

Measured El patterns@ 1.7 - 2.2GHz

0 and 10⁰ beam tilt

2-pol dipoles (34EA)

1.7GHz 2.2GHz


View from behind antenna looking outward:

8°

~90°

2x9-Beam Stadium Antenna 2x9NPA2010F

Frequency Band, MHz

1710–1920

1920–2170

Gain, dBi 25.0 27.0

Beamwidth, Horizontal, degrees

6 5

Beamwidth, Vertical, degrees 7.2 5.8

USLS, dB 18 18

Front-to-Back Ratio at 180°, dB

30 30

Isolation, dB 16 16

VSWR | Return Loss, dB

1.43 | 15.0

1.43 | 15.0

PIM, 3rd Order, 2 x 20 W, dBc -150 -150

100 of 2-pol radiatingelements locatedin triangular lattice

Horizontal and vertical sectorization is used


2-band 2-Beam Antenna 2UNPX206.12R2

25% bandwidth in both bands

698-894 + 1710-2170MHz


Dual Band Interleaved Base Station Phased Array Antenna With Optimized Cross-Dipole and EBG/AMC Structure. Fayez Hyjazie, Paul Watson, and Halim Boutayeb, IEEE AP-S, Memphis, 2014, p. 1558

Challenges

• Simple Butler matrixes (shown in slide 5)are working OK for relatively narrowband (say, 1.7-2.2GHz, see slide 5,6)

• Introduction of new bands (LTE2.6 andLTE3.5) requires wider bandwidth 1.7 -2.7 GHz (or even 1.7-3.8GHz) causessignificant beam width and beamposition variations, SL increasing

Solutions

• Solution 1: make amplitude distribution in antenna array depending on frequency: - filters; - frequency dependent power dividers; - Solution 1 adds complexity: about 3 times more components

• Solution 2: lensed antennas (see Part 2)

1.7-2.1GHz

2.5 -2.7GHz

Narrowing beam effect Grating lobes\side lobes

Frequency-dependentdivider

φ

Beam walking effect

Challenges and Solutions for Wideband Array


2-Beam Wideband Antenna Array

Frequency-dependentdivider

1.7 – 2.7 GHz array

“Clover” dipole and tightly coupled dipoles are candidates

for ultra-wideband 2-beam


Example:Radar jamming32 beams2-pol 50% bandwidthLate 70s

Part 2: Lensed Multi-Beam BSA

Homogeneouslens

Multi-layer LunebergLens: ε = 2 – (r/R)²

RF lenses: A Lot of Defense Applications, New for BSA


3-H24A-3XR: High Performance Tri-Beam· 1710–2180 MHz• 3 x 24º beams• 10 dB roll-off between sectors• Gain ~22 dBi• <-18 dB horizontal sidelobes• Cross-pol ratio > 10dB over cell sector• Individual remote electrical tilt (RET)

0- 10⁰ for each of 3 beams• >30dB isolation between all ports• Use of artificial dielectric (US patent

8518537) significantly reduce antenna weight and cross-polarization level

• Low wind load (3 times less compare to equivalent Butler matrix array)

Cell plan and sectorizationresulting from 3-beam

lensed antennas

Cross-pol


Wideband Tri-Beam 1.7 – 2.7GHz

-3dB

-10dB

-3dB

With lens

W/o lens1.7GHz2.2GHz2.7GHz

• Stable azimuth beamwidth: 23+/-2⁰ (-3dB level); 40+/-3⁰ (-10dB level)

• Stable beam position (+/-1.5⁰ of nominal) and beam cross-over -10+/-3dB

• Low azimuth sidelobes, decreased elevation grating lobes (by ~5dB)

Measured patterns

Box-type element itself

Phase shifter+actuator

• With the same lens and the same size, 4-beam can obtained: only 2 antennas per cell site for 360⁰ coverage

• 120⁰ coverage, 3 antennas only per cell site

– 4 beam (with the same lens): 180⁰ coverage, only 2 antennas per cell site


Wideband and Dual-Band Lensed Antennas

f₁

f₂

2-pol box-type antenna element is candidatefor wideband and dual-band lensed antennas

• Beam position for lensed antenna does not depend on frequency; but need take care about beamwidth.

• Beam width stabilization can be achieved by using antenna element with beam width monotonically decreasing with frequency. Example: box-type element.

• In the result, lens effective radiating aperture is also decreasing with frequency and beam of whole antenna is not depending on frequency.

• 2-band array solution is shown below: box-type elements for low band (LB, 698 – 960MHz) plus combination of box elements and pairs of cross-dipoles for HB (1.7 -2.7GHz).

f₁ < f₂ ; S₁ > S₂; if S₁ / S₂ = λ₁ / λ₂, Az BW = const

Example of 2-band feed array for dual-band lensed antenna

LB HB


A lensed BSA has the following performance advantages over planar array Butler matrix technology:

• Higher gain efficiency (less insertion loss)• Exceptional port-to-port isolation (typically,

10 -15dB better)• No pattern distortion or scanning gain loss

for outer beams• 25 -30% narrower (with the same Az BW)• Significant (3 times) lower frontal and rear

wind load (thanks to rounded shape and better aperture efficiency)

• Lighter weight (typically, by 30%)• Excellent independent beam tilt

performance; extended tilt OK (say, 0-20⁰)• Excellent stability of beam cross-over level,

beam pointing and beam roll-off• Excellent azimuth and elevation sidelobe

suppression (grating lobes)• Wider max coverage (180⁰ typ. vs. 100⁰ typ.

for cylindrical; up to 360⁰ for spherical lens)

A lensed BSA has the following performance disadvantagesover planar array Butler matrix technology:

• 1.5 – 2 times deeper• 30% - 50% higher

lateral wind load

Performance Comparison


Thank-you!

Questions?

Multi-Beam Base Station Antenna · PDF fileDual Band Interleaved Base Station Phased Array...

Documents

Transcript of Multi-Beam Base Station Antenna · PDF fileDual Band Interleaved Base Station Phased Array...