4G Fiberglass Antenna for Cellular Communication

　　Technical Application of 4G Glass Fiber Antenna in Cellular Communications

　　The coverage quality (RSRP≥-110dBm ratio) and capacity density (500+ users per square kilometer) of cellular communication networks are highly dependent on the radiation characteristics of base station antennas. 4G glass fiber antennas have become core components of macro, micro and indoor distribution systems with their wideband coverage (698-2690MHz), weather-resistant design (-40℃ to 70℃) and gain adjustability (6-18dBi). Its value in cellular networks is not only reflected in the extension of signal coverage radius (20% increase over traditional antennas), but also in the increase of edge user throughput by more than 30% through beamforming and polarization optimization.

　　Core technical requirements of cellular communications for antennas

　　Multi-band compatibility

　　4G cellular networks adopt a multi-band layered coverage strategy: 700/850MHz (low band) is responsible for wide area coverage, 1800MHz (mid-band) balances coverage and capacity, and 2600MHz (high band) carries hotspot capacity. Glass fiber antennas need to achieve full-band matching through a stepped oscillator design, with a standing wave ratio of ≤1.5 in each frequency band. In the 700MHz band, the radiation efficiency is ensured to be ≥85% by increasing the oscillator length (λ/2=21cm), and in the 2600MHz band, the mutual coupling interference is reduced by shortening the oscillator spacing (λ/4=28mm).

　　Actual measurement data shows that a glass fiber antenna covering 698-2690MHz can achieve a gain of 14dBi in the 1800MHz band, which is 60% lower than the switching loss (0.5dB) of a single-band antenna, and is particularly suitable for cellular networks with multi-band collaborative networking.

　　Polarization and MIMO adaptation

　　4G LTE's MIMO technology (2×2/4×4) requires the antenna to have dual polarization characteristics (±45° cross polarization), and the cross polarization discrimination (XPD) ≥20dB@60° incident angle to ensure that the spatial diversity gain (2-3dB) is effectively obtained. The glass fiber antenna achieves polarization isolation through the orthogonal arrangement of symmetrical oscillators. The isolation in the 2.6GHz frequency band is ≥25dB, which is much better than the single-polarization antenna (15dB), and can increase the MIMO throughput by 50%.

　　For indoor micro-station scenarios, a vertical + horizontal dual polarization combination is adopted. In a multipath-rich environment (such as an office building), the channel rank (Rank) can be increased from 2 to 3, supporting higher-order modulation (64QAM→256QAM), and the single-user rate is increased by 25%.

　　High-gain solution for macro station deployment

　　Directional beam focusing design

　　The macro station fiberglass antenna adopts a 12-unit array + reflector structure. The horizontal beam width can be customized on demand (30°/65°/90°). The horizontal beam of the 18dBi high-gain model is only 30°, and the energy concentration in the main lobe direction is 10 times that of the omnidirectional antenna. Through the combination of mechanical downtilt (0°-10°) and electrical downtilt (0°-15°), the coverage range can be accurately controlled:

　　Suburban wide coverage: 30° horizontal beam + 5° downtilt, coverage radius up to 10km

　　Urban capacity layer: 65° horizontal beam + 8° downtilt, balancing coverage and interference

　　The reflector adopts aluminum alloy nickel plating technology (thickness 2mm), suppressing the back lobe to below - 25dB (front-to-back ratio ≥ 25dB), reducing the same-frequency interference to the neighboring area (reduced by 10dB), and improving the cell edge SINR by 5dB.

　　Wind load and installation adaptation

　　The installation height of the macro station antenna is 30-50 meters, and it needs to withstand the wind pressure load (≥2000Pa) of a 12-level typhoon (32.7m/s). The glass fiber antenna has a streamlined antenna cover design (drag coefficient Cd=0.6), which reduces the wind load by 25% compared with the traditional metal antenna (Cd=0.8). With the reinforced flange (thickness 10mm), there is no structural deformation under 100kN axial tension.

　　During installation, the pole type is used for fixing (diameter 50-114mm), and the torque is controlled at 50N・m to ensure that the azimuth deviation is ≤±1° (each 1° deviation causes 3dB gain loss). Through GPS-assisted calibration, the overlapping area of the three-sector antenna (120° coverage) is ≤5%, avoiding dropped calls caused by too wide switching band.

　　Flexible solutions for micro-stations and indoor coverage

　　Low-profile omnidirectional design

　　The street micro-station and indoor distribution system use low-gain omnidirectional antennas (6-8dBi), with a horizontal beam of 360° to ensure no coverage blind spots, and a vertical beam width of 30°-45° to balance ground and floor coverage. The low-profile characteristics of the fiberglass material (thickness ≤20mm) allow it to be concealedly installed on street lamp poles, ceilings, etc., with a degree of integration with the environment of 90%.

　　When deployed in a 500㎡ shopping center, an 8dBi ceiling antenna (spacing 8-10 meters) is used. Through distributed coverage, the proportion of indoor RSRP ≥-95dBm areas reaches 98%, supporting 100+ concurrent users (1Mbps bandwidth per person).

　　Anti-interference and penetration loss optimization

　　For indoor wall penetration loss (concrete wall 15-20dB), the glass fiber antenna adopts a wide-band low-loss design, and the penetration loss compensation in the 1800MHz frequency band is ≥6dB. With intelligent power control (TPC), the indoor and outdoor signal switching success rate is ≥99.5%.

　　In strong interference environments such as industrial plants (electromagnetic noise ≥-85dBm), the antenna integrates a bandpass filter (698-2690MHz), and the interference suppression of the frequency band below 1.5GHz is ≥40dB, ensuring that the signal-to-noise ratio (SNR) of the LTE signal is ≥15dB, meeting the VoLTE voice quality requirements (MOS ≥4.0).

　　Co-optimization with cellular networks

　　Beamforming and cell breathing

　　Through digital beamforming (DBF) technology, the fiberglass antenna can dynamically adjust the beam width (30°-90°), compress the beam to 30° during peak traffic hours (such as morning commuter rush hour), and increase the signal strength in hot spots by 5dB; expand it to 90° during off-peak hours to expand coverage. This cell breathing function increases sector capacity utilization from 70% to 85%.

　　In high-speed rail scenarios, by tracking the beam (beam switching speed ≤5ms) and compensating for the Doppler frequency deviation (±1.2kHz) caused by the high-speed movement of the train (350km/h), the switching success rate is maintained at more than 99.8%, and the call drop rate is ≤0.05%.

　　Key indicators for network optimization

　　Coverage indicators: Edge RSRP ≥ -110dBm, SINR ≥ 3dB, ensuring 16QAM modulation and demodulation

　　Capacity indicators: Single-sector throughput ≥ 50Mbps (downlink) / 10Mbps (uplink), supporting 200 + activated users

　　Interference indicators: Co-frequency neighbor interference ≤ -100dBm, inter-frequency interference ≤ -90dBm, IMD3 ≤ -15dBc

　　Typical deployment scenarios and performance data

　　Rural macro station coverage

　　In a rural area with a radius of 10km, 18dBi glass fiber directional antennas (700MHz band) are deployed, using 4-sector networking, and a 2° beam downtilt design to increase the coverage edge RSRP from - 115dBm to - 108dBm, meeting the basic communication requirements of 4G LTE Cat.4 terminals (download ≥ 5Mbps). The antenna adopts a bird-proof design (with a slope baffle installed on the top) to reduce signal obstruction caused by bird roosting (attenuation ≤ 1dB).

　　Urban micro-station blind spot filling

　　Deploy 12dBi fiberglass omnidirectional antennas (1800MHz) in urban villages and install them on 8-meter-high lamp poles. The horizontal beam is 360° to ensure that there are no blind spots in the alleys. Through the heterogeneous network with the macro station (macro station 700MHz + micro station 1800MHz), the indoor signal strength is increased from -110dBm to -95dBm, and the user complaint rate is reduced by 60%.

　　Indoor distribution of large venues

　　The stadium uses distributed fiberglass antennas (8dBi, 2600MHz) with a spacing of 15 meters. Through MIMO 2×2 technology, when the stadium is full of 50,000 people, the single-user downlink rate is still maintained at 15Mbps, which is 50% higher than the traditional indoor antenna (10Mbps), meeting the live broadcast upload requirements of the event.

　　The application of 4G glass fiber antennas in cellular communications has achieved full-link optimization from signal coverage to user experience. Its technical evolution will focus on frequency band integration with 5G NR (Sub-6GHz), intelligent beam tracking, and AI-driven network self-optimization, providing continuous support for ubiquitous connectivity in future cellular networks.