4G Fiberglass Antenna Signal Strength Optimization

　　4G fiberglass antenna signal strength optimization technology

　　The signal strength of 4G fiberglass antenna (usually measured by received power RSRP, in dBm) directly determines the communication quality. Increasing from -100dBm to -85dBm can increase the download rate by more than 3 times. Signal strength optimization requires systematic measures from three dimensions: electromagnetic design, installation and debugging, and environmental adaptation. Performance leaps can be achieved by reducing losses, enhancing gains, and suppressing interference.

　　Signal enhancement at the hardware design level

　　Radiation unit topology optimization

　　The Yagi antenna array structure is adopted, and 3 reflectors, 1 driving oscillator and 4 directors are integrated in the fiberglass shell. The gain is increased to 14dBi (6dB more than the single oscillator design) by adjusting the unit spacing (0.35λ-0.5λ). The driving oscillator is made of copper-plated silver (thickness 5μm), which reduces the high-frequency skin effect loss (reduced by 0.8dB in the 2.6GHz frequency band), and increases the radiation efficiency from 80% to 92%.

　　Impedance matching network fine tuning

　　The 50Ω system impedance matching is achieved through a step impedance transformer (composed of 5 microstrip lines), and the standing wave ratio is controlled below 1.3 in the full frequency band of 698-2690MHz (the traditional design is 1.7). In the 700MHz low frequency band, an LC parallel resonant circuit is used to compensate for the dielectric loss of the glass fiber shell (impedance shift caused by εr=3.2), reducing the signal transmission loss in this frequency band by 1.2dB.

　　Application of low-loss materials

　　The antenna cover uses low dielectric loss glass fiber (tanδ=0.0015), which reduces signal absorption by 50% compared with ordinary glass fiber (0.003). The internal feeder uses a physical foamed polyethylene (PE) dielectric cable (loss ≤ 0.3dB/10m@2GHz) with an N-type stainless steel connector (insertion loss ≤ 0.15dB) to control the entire signal link loss within 0.5dB.

　　Signal optimization during installation and commissioning

　　Precise calibration of beam pointing

　　Use a vector network analyzer (VNA) combined with satellite positioning to control the azimuth deviation of the antenna main lobe direction and the nearest base station (queried by Cell ID) within ±1°. Test data shows that every 1° deviation will cause 3dB signal attenuation. At a distance of 10 kilometers, precise alignment can increase RSRP from -105dBm to -99dBm. For omnidirectional antennas, ensure that the vertical elevation angle is 5° (not horizontal placement), and use ground reflection to enhance signal coverage (increase the strength of the edge area by 4dB).

　　Multi-antenna diversity deployment

　　Spatial diversity technology is used in scenarios such as vehicles and base stations. The distance between the two antennas is ≥λ/2 (≥21cm for the 700MHz frequency band). The deep signal fading is avoided by selecting a merging algorithm (response time < 10ms). Actual measurements show that in urban buildings, diversity reception can reduce the signal interruption time from 200ms/hour to 15ms/hour, and the call drop rate from 1.2% to 0.1%.

　　Grounding and shielding treatment

　　The antenna base is connected to the grounding electrode through a copper tape (cross-sectional area 6mm²), and the grounding resistance is ≤4Ω to avoid signal interference caused by static electricity accumulation (noise floor is reduced by 3dB). For industrial environments, a metal shielding net (aperture <λ/10) is set within 3 meters around the antenna to attenuate the 2.4GHz interference signal by ≥40dB, ensuring that the 4G signal signal-to-noise ratio (SNR) is increased to more than 20dB.

　　Environmentally adapted anti-interference strategy

　　Multipath effect suppression

　　In urban canyons or metal reflection environments, polarization diversity design (±45° dual polarization) is adopted to select the optimal path by comparing the amplitude of two orthogonal signals, which can reduce the multipath fading depth from 20dB to 8dB. With the adaptive equalization algorithm (implemented on the modem end), multipath signals with delay spread ≤100ns are effectively merged to increase data throughput by 30%.

　　Frequency band adaptive switching

　　The signal strength of each frequency band is detected in real time through the frequency scanning monitoring module (scanning 100 times per second), and it automatically switches between 700MHz (good coverage) and 2600MHz (large capacity). When the interference level of a certain frequency band is ≥-85dBm, it switches to the backup frequency band within 0.5ms to avoid communication interruption caused by sudden interference (such as radar signals).

　　Extreme weather protection

　　In thunderstorm areas, the antenna integrates a gas discharge tube (breakdown voltage 90V), which conducts overvoltage to the ground within 100ns after lightning strikes to avoid damage to the front-end LNA (signal strength retention rate after protection ≥95%). In high temperature environments (≥60℃), a temperature compensation circuit is used to control the resonant frequency offset of the oscillator within ±5MHz (standard is ±15MHz) to ensure stable signal reception.

　　Signal optimization cases in typical scenarios

　　In-vehicle mobile scenarios

　　Through the Doppler frequency offset compensation algorithm (integrated in the antenna driver module), the frequency offset is corrected from ±1.2kHz to ±0.1kHz at a speed of 120km/h, reducing the demodulation bit error rate from 10⁻⁵ to 10⁻⁷. With the magnetic adsorption low-profile installation (height ≤8cm), the vibration loss caused by high-speed wind resistance is reduced (the signal fluctuation amplitude is reduced from ±6dB to ±2dB).

　　Rural wide area coverage

　　Using high-gain narrow beam antenna (16dBi, horizontal beam 45°), signal focusing is achieved through beam compression at a distance of 15 kilometers, and RSRP is increased from -110dBm to -98dBm. At the same time, a metal reflector (area 0.5m²) is installed at the bottom of the antenna to reflect the radiation energy of the lower hemisphere into the air, enhancing the uplink signal to the distant base station (PUCCH channel quality is improved by 5dB).

　　Industrial plant environment

　　In view of the metal structure shielding in the factory, a distributed antenna system (DAS) is deployed to achieve uniform signal coverage through multiple low-power fiberglass antennas (8dBi). In the production line area, the antenna adopts a thin design (thickness 3mm) with a penetration loss of ≤6dB and is installed on the outside of the metal pipe, so that the RSRP in the workshop is kept in the ideal range of -85dBm to -75dBm.

　　Signal strength test and verification method

　　Key indicator monitoring

　　Received power (RSRP): measured by a frequency sweeper at 3 meters from the antenna, should be ≥-95dBm (urban), ≥-105dBm (rural)

　　Signal quality (SINR): should be ≥15dB during busy hours to ensure 150Mbps rate of 4G LTE Cat.6

　　Interference level: In-band spurious signals should be ≤-100dBm/100kHz to avoid interference to neighboring areas

　　Optimization effect verification

　　The 4G glass fiber antenna after system optimization should meet the following requirements:

　　Coverage: 50% larger than before optimization (with RSRP=-110dBm as the boundary)

　　Communication availability: 99.99% (interruption time ≤52 minutes per year)

　　Rate stability: download rate standard deviation ≤5Mbps (in 10 Signal strength optimization is a systematic project, which requires the coordination of hardware characteristics, installation environment and communication protocols. Through continuous monitoring and dynamic adjustment, the 4G fiberglass antenna can always maintain the best performance in complex scenarios.