Metalenses Antenna’Solutions for High Speed Railway Scenarios
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Metalenses Antenna’Solutions for High Speed RailwayScenarios With the continuous improvement of China's high-speed railway, it has become more important to achieve comprehensive coverage of 5G signals in high-speed railway scenarios. A high-speed railway scenario has a special wireless network environment, e.g., high speed of the railway, and great penetration loss. It is a great challenge when problems come to building high-quality network coverage for mobile communication network construction in high-speed railway carriages with high running speeds, high passenger volumes, huge business volumes, and complicated deployment scenarios.It is reported that the increasing coverage mileage of high speed railwayin 2021~2024 reaches about more than 10,000 kilometers, and high speed railwayhas become the main tool of China's transportation, and the coverage of mobile communication network of high speed railwaylines has become a topic we must pay attention to.
The main problems of coveragein high speed railwayscenario: (1) The cover area along the high-speed railway is linearly distributed, and due to the existence of the general track bed with relatively narrow width and long track depth, while the traditional antenna has a large HBWand a narrow VBW, and the actual distance of thebase stationsignal projected to the track is short, most of the signal is covered beyond the track, resulting in a waste of coverage. (2) Frequent signal switching, users are easy to be offline, greatly affecting the user experience. (3) high speed railway5G application are selecting mediumor high frequencyband, andpenetration loss is relatively largein the carriages, so there are problems in the coverage by using the current signals from spacing between station and station, and it increasestheinvestmenton stations. Problem Analysis: When the main beam of the base station antenna has a large angle between the ground projection and the high speed railway railline, it will directly lead to holes in vertical coverage, and when the VBWof the antenna gettingwider, the number and the impact of holes in vertical coverage will be correspondingly smaller. Therefore, for the coverage of high speed railwayscenarios, it is more necessary to use antennas with largeVBW. Sigtenna solution: Sigtenna Metalensesantenna can use fewer dipolesto make the electromagnetic beamsignals converge into electromagnetic beam signalswith high-gainand narrowbeam, and all the energy is more concentrated in the direction of the main lobe, and the secondary lobeis smaller, so the antenna'sHBWis compressed to a narrow beam of about 30 °, which is in line with the coverage along therailwaylineand reduces the waste of the coverage.The VBWis compressed to about 20 degrees, the vertical projection is longer to the railway line, and the distance along the railwayis longer, so the VBWof the lens antenna is greatly improved compared with the traditional antenna, and while the gain of the lens antenna is still maintained at a better level, the reduction of the VBWhas less impact on the coverage of the high speed railwayscenario, so it can be seen that its coverage ability in the high speed railwayscenariohas been more obviously improved compared with the traditional antenna. |
Regular Panel Antenna Radiation Direction Patterns Metalense Antenna Radiation Direction Patterns
Problem solution 1: the antenna has higher gain and efficiency with more than the double coverage distance, and fewer blind zones under the tower, which reduces signal switching and save more than 50% of the station investment, and increase the average field strength by about 10DB.
Problem Solution 2: Compared with the same coverage area as an ordinary antenna, the Metalenses antenna can reduce the transmit power of the equipment by about 50%, reduce energy consumption, and save electricity costs because it is more efficient.
Same Power,improving the coverage distance
Improving the efficiency
Normal Antenna
Same coverage, decreasing RRU power rate
Problem solution 3: According to 3GPP and other standardization requirements for mobile working delay <1S, the maximum delay distance does not exceed 83 meters. The application of the HBW 30° narrow beam antenna in the station track moment > 80 meters, covering a distance of 1 kilometer, will form a 100-meter coverage of the blind zone. However, Sigtenna products can be customized according to the station track distance and coverage distance of the horizontal wave width and gain indicators.
Simulation of weak coverage with narrow beam antennas at 0° horizontal plane
Simulation diagram of antenna’s coverage area at 30° HBW
Simulation diagram of antenna’s coverage area at 45° HBW
Problem solution 4: Flexible selection according to the scenarios:
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Coverage distance and station spacing selection |
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Product Type |
Frequency Band |
Gain |
HBW |
spacing distance |
Coverage distance |
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Single beam meta lens antenna |
1710-2690 |
14.5 |
33 |
＜120 |
＜600 |
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16 |
33 |
80-120 |
＜1000 |
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17 |
45 |
120-200 |
＜1200 |
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19 |
30 |
＜80 |
＜1600 |
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17 |
45 |
120-200 |
＜1200 |
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19 |
90 |
＞200 |
＜1600 |
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Applications:
Application case 1:
Nanjing Shishu Lake Bridge with the length about 12.8 kilometers, is for the dual-purpose to highway and light rail, and the middle of the lake can not build base stations. The operator uses 1800M frequency band for coverage test. The original station has been installed the Lunberg lens antenna, but covered only 3.5 kilometers. However, when it was replaced with Sigtenna Metalenses antenna, the antennas are installed at each end of the bridge, and the rate of coverage can reach 95%.
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技术指标名称technical indicators |
原有友商龙伯球天线 Lunberg antenna from other competitors |
司南透镜天线 Sigtenna Metalensesantenna |
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工作频段(MHz) Frequency Range(MHz) |
1710-2690MHz |
1710-2690MHz |
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极化方式 Polarization |
±45°极化 |
±45°极化 |
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增益(dBi) Gain(dBi) |
19 |
21 |
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frequency band |
4G average RSRP |
4G average SINR |
4G average downlink rate (Mbps) |
Coverage rate (RSRP ≥ -105dBm & SINR ≥ -3dB) |
Coverage distance (1 pcs antenna) |
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before replacement |
1800 |
-94.8 |
-0.84 |
8.37 |
45.60% |
3km |
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after replacement |
-85.12 |
10.24 |
42.46 |
90.01% |
5.6km |
Application Case 2:
Changjing Huang High Speed Railway is part of Hangzhou-Changzhou High Speed Railway. In the section of Huangshan-Nanchang, the station spacing on both sides of Jinxi Lake Bridge is more than 6.5 kilometers, and the base station cannot be built in the middle, so there is a risk of no signal coverage for about 4- kilometers on the bridge. Meanwhile, there is a need to support the 1800 MHz 2TR, 2000 MHz 2TR, and 2600 MHz 8TR frequency bands to complete the coverage of the bridge. Among them, 2600 MHz distance loss and high-speed railroad car penetration loss are the biggest, which is the difficult point of this coverage. By using a multi-frequency and multi-layer networking scheme, a regular high-gain metalens antenna with a gain of 17 dBi achieves near-middle-point coverage, while a custom 22 dBi ultra-high-gain metalens antenna achieves far-point coverage and ultimately jointly achieves 1800 m and 2.6 g coverage.
Coverage Scenarios
Specifications of pilot products
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technical indicators |
12-port single-beam Middle frequency 17dBi metalenes antenna (near point) |
12-port single-beam Middle frequency 22dBi metalens antenna (farpoint) |
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Frequency Range(MHz) |
1800M |
FA |
D |
1800M |
FA |
D |
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1710-1880 |
1885-2025 |
2515-2690 |
1710-1880 |
1885-2025 |
2515-2690 |
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Polarization |
±45°Polarization |
±45°Polarization |
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Gain(dBi) |
>16.5 |
>17.5 |
>17 |
>21 |
>21.5 |
>22.5 |
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Horizontal beamwidth(°) |
31°±2 |
29°±2 |
28°±2 |
30°±1 |
26°±0.5 |
22°±2 |
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Vertical beamwidth (°) |
17.5°±1 |
17°±0.5 |
18°±1 |
8°±0.5 |
7°±0.5 |
7°±0.5 |
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Dimension |
1510x610x310 mm |
2300x500x310 mm |
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Test results
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Standard |
Frequency Range |
The Percentageof RSRP bigger than -110 |
The Percentageof RSRP bigger than -105 |
Average RSRP |
Coverage rate (RSRP≥-110&SINR≥-3） |
Average SINR |
Average speed rate（Mbps） |
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5G |
2600M |
100% |
98.19% |
-88.48 |
100% |
13.88 |
204.1 |
RSRPSINR
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Standard |
Frequency Range |
The Percentageof RSRP bigger than -110 |
The Percentageof RSRP bigger than -105 |
Average RSRP |
Coverage rate (RSRP≥-110&SINR≥-3） |
Average SINR |
Average speed rate（Mbps） |
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4G |
1800M |
100% |
100% |
-85.77 |
99.46% |
13.94 |
39.89 |
RSRP SINR
IPV4 / IPV6