Dual-band and Dual-polarized Antenna for LTE Femto/Pico-cell Basestation Applications

Ting-Jui Huang and Heng-Tung HsuDepartment of Communications Engineering,Yuan Ze

University

Outline

• Introduction• Literature Review• Simulation and measurement Results• Summary

2

Introduction• Nowadays different mobile communication systems have been

designated with different frequency bands.

2G systems : GSM900/GSM1800 and CDMA(Center at 900 MHz (825–960MHz) and 1800 MHz (1710–1920 MHz))

3G systems : WCDMA/cdma2000, TDCDMA and WiMAX (Center at 2 GHz (1880–2170 MHz)

LTE (4G) systems : VoLTE/CSFB and SVLTE (Center at820MHz (689-960MHz) and 2.2GHz(1710-2690MHz))

3

LTE Band

• 4G Spectrum Allocation in Taiwan: Band 3 1800MHz Band 8 900MHzBand 28 700MHz.

A.700MHz - Band 28：uplink 703-748MHz/downlink 758-803MHz

B.900MHz - Band 8：uplink 885-915MHz/downlink 930-960MHz

C.1800MHz - Band 3：uplink 1710-1770MHz/downlink 1805-1865MHz

LTE Basestation Type

• Standard base station(Macrocell) :35 km

• Microcell :2 km• Picocell :200 m• Femtocell :10 m

Literature Review (1/3)CN202231146U_201120352736.7_SIPO

• 3 : Lower band radiator• 4 : Dual polarization

upper band radiator• 21 : High pass filter• 22 : Low pass filter

Literature Review (2/3)CN203071229U_201320020787.9_SIPO

41 42 : Upper band radiator43 : Lower band radiator50 : feeding network

Literature Review (3/3)“Broadband Dual-Frequency and Dual-Polarized Antennas for GSM/3G/LTE Base Stations”

Cont.(Base Station Application)

Broadband dual frequency antennaGain: lower band up to 12dBi

upper band up to 13dBiPolarization: Linear

Broadband dual polarized antennaGain: up to 15dBiPolarization: +45o & -45o

Antenna Design Challenge

• Wide Bandwidth (Low band 698MHz-960MHz 31.6%Up band 1710MHz-2690MHz 44.5%)

• Dual Polarization (MIMO Application)• High gain• Directive Radiation Pattern• Capability of Smart Antenna Implementation

Antenna ConfigurationWideband Dipole Antenna

Hsu, H.-T.; Huang, T.-J., "Generic dipole-based antenna-featuring dual-band and wideband modes of operation," Microwaves, Antennas & Propagation, IET , vol.6, no.15, pp.1623,1628, December 11 2012

Antenna Performance at Lower Band

End loading reduce the size

End loading reduce the size

Antenna Performance at Upper Band

Antenna Performance at Both Bands Using Separate Ports

Antenna Performance at Both Bands Combined with Feeding Network

Diplexer

Use CST Design Studio to realize feeding network.

Radiation Patterns698MHz 860MHz 960MHz

1770MHz 1990MHz 2700MHz

Array Implementation Realizing Dual Polarization

+45 degree polarization

-45 degree polarization

Fabricated Prototype and Measurement Results

0.0 0.5 1.0 1.5 2.0 2.5 3.0-50

-40

-30

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-10

0

S11

(dB

)

Frequency (GHz)

-45 Degree 45 Degree

Measured Gain• LTE lower band =0.698MHz-0.960MHz (>6dBi)• LTE Upper band =1710MHz-2700MHz (>7dBi)

0.50 0.75 1.00 2.0 2.5 3.0

2

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simulation measurement -45degree measurement 45degree

Gai

n (d

Bi)

Frequency (GHz)

Measured Radiation Pattern

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806MHz Co-polar 806MHz X-polar

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2600MHz Co-polar 2600MHz X-polar

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1990MHz Co-polar 1990MHz X-polar

806MHz 1990MHz 2600MHz

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806MHz Co-polar 806MHz X-polar

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1990MHz Co-polar 1990MHz X-polar

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2600MHz Co-polar 2600MHz X-polar

XZ-plane

YZ-plane

Envelope Correlation Coefficient from S-parameter

Diversity Gain from S-parameter

Envelope Correlation Coefficient from FarField Result

Diversity Gain from FarField Result

Summary

• We have presented the design, analysis, and measurement results of a dual-band, dual-polarized antenna for LTE basestation applications.

• The antenna featured complete frequency coverage in 4G LTE bands with good gain performance.

• The agreement between the simulation and measurement results has proven the effectiveness of CST in MIMO antenna designs.