4G Fiberglass Antenna Compatibility with Routers

　　Compatibility analysis of 4G fiberglass antenna and router

　　The compatibility of 4G fiberglass antenna and router directly determines the signal enhancement effect of home network. The core lies in the three-dimensional coordination of interface matching, frequency band coverage and power adaptation. In actual applications, about 30% of signal enhancement failure cases are caused by compatibility issues (such as 3dB loss caused by interface mismatch) rather than insufficient antenna performance. By scientifically evaluating the matching degree of router parameters and antenna characteristics, the collaborative work efficiency can be increased to more than 95%, ensuring the expected effect of RSRP (reference signal received power) improvement of 10-15dB.

　　Physical compatibility of interface types

　　Adaptation rules of mainstream interfaces

　　The external antenna interface of the router 4G module is mainly SMA and N-type. Among them, consumer-grade routers (such as Huawei B315) mostly use SMA female connectors (external thread + hole), and industrial-grade CPE (such as ZTE MC8020) commonly use N-type female connectors (internal thread + hole). The corresponding fiberglass antenna needs to be equipped with a matching male connector:

　　SMA male connector (external thread + pin): suitable for consumer-grade routers, thread diameter 3.5mm, torque controlled at 8-10N・m, over-tightening will cause the interface to slip

　　N-type male connector (internal thread + pin): suitable for industrial-grade equipment, thread diameter 16mm, torque 15-20N・m, to ensure effective deformation of the waterproof seal (nitrile rubber)

　　Some old routers use TNC interfaces (with positioning pins), and TNC-N adapters (insertion loss ≤ 0.3dB) are required to avoid signal leakage caused by forced modification (loss can reach 5dB). The interface material is preferably brass nickel-plated (salt spray resistance ≥ 500 hours), which is better than zinc alloy (oxidation after 200 hours).

　　Interface impedance matching requirements

　　The output impedance of the router RF front end is standard 50Ω, and the input impedance of the fiberglass antenna must be strictly matched (deviation ≤5Ω), otherwise reflection loss will occur (corresponding relationship between standing wave ratio VSWR and loss: 1.5:1→0.15dB, 2.0:1→0.5dB, 3.0:1→2.5dB). Test data shows that when the impedance deviation between a certain 8dBi fiberglass antenna and the router reaches 10Ω, the actual gain drops from 8dBi to 5.8dBi, and the signal enhancement effect is reduced by 27%.

　　The impedance matching can be measured by a vector network analyzer (VNA). In the 1800MHz frequency band, the return loss of a high-quality antenna should be ≥15dB (VSWR≤1.4), ensuring that the signal transmission efficiency is ≥96%. For DIY modification scenarios, a 50Ω matching resistor (power ≥1W) can be connected in series at the interface to compensate for slight impedance mismatch (≤7Ω).

　　Electrical compatibility of frequency band coverage

　　Matching of router frequency band and antenna

　　The frequency band supported by the 4G router needs to completely overlap with the coverage of the fiberglass antenna, otherwise there will be a "frequency band blind spot". For example:

　　A router that only supports B1 (2100MHz)/B3 (1800MHz) is fully compatible with a full-band antenna covering 698-2690MHz

　　A rural-specific router that supports the B8 (900MHz) low-band will cause a 15dB attenuation of the 900MHz band signal if it is misused with an antenna that only covers 1700-2700MHz

　　Judgment method: Check the "Supported Frequency Bands" in the router manual (such as LTE FDD: B1/B3/B5/B8), and select a fiberglass antenna that fully includes the frequency band parameters (such as the label "698-2690MHz full band"). For multi-band routers, the gain deviation of the antenna in each band should be ≤2dB (such as 1800MHz10dBi/900MHz8dBi) to avoid a certain band becoming a performance bottleneck.

　　Polarization compatibility of mimo system

　　Routers that support MIMO 2×2 (such as Huawei B525) need to be equipped with dual-polarized glass fiber antennas (±45° cross-polarization). Single-polarized antennas will cause the second signal to be completely ineffective (rate halved). The port isolation of dual-polarized antennas must be ≥20dB (in the 1.8GHz band) to avoid mutual interference between the two signals (when the isolation is less than 15dB, the throughput drops by 30%).

　　The mimo antenna interface of the router is usually marked with the primary and secondary differences (such as ANT1/ANT2). When installing, the two interfaces of the antenna must be connected one by one, and they must not be cross-confused (which will cause a loss of 2-3dB in polarization diversity gain). Some high-end routers support antenna diversity switching, which can automatically select the channel with a stronger signal, but it is still recommended to strictly correspond to the connection for the best effect.

　　Cooperative compatibility of power and gain

　　Adaptation of router transmission power

　　The maximum transmission power (EIRP) of a 4G router is usually 23dBm (200mW), and the gain of the fiberglass antenna needs to be controlled within a reasonable range:

　　Consumer-grade router (23dBm): with a 6-10dBi antenna, the total radiated power is ≤33dBm (in line with ETSI standard limits)

　　Industrial-grade router (27dBm): It is recommended to use a 6-8dBi antenna to avoid exceeding the standard (35dBm is the upper limit)

　　Excessive gain (such as 18dBi) will cause the signal to be too strong, triggering the router's power suppression protection (reducing power by 3-5dB), which will reduce the actual coverage range. Tests show that when a 23dBm router is paired with a 12dBi antenna, the edge signal strength is 2dB weaker than the 10dBi solution due to power suppression.

　　Matching of receiving sensitivity

　　The receiving sensitivity of the router 4G module is usually - 110dBm@1% BER (bit error rate), and the gain of the glass fiber antenna needs to be coordinated with this parameter:

　　In the strong signal area (RSRP≥-85dBm): 6dBi antenna can meet the demand, and high gain is more susceptible to interference

　　In the weak signal area (RSRP=-100~-110dBm): 10dBi antenna can increase the received signal to - 90~-100dBm, which falls into the module's optimal receiving range

　　In the extremely weak signal area (RSRP<-110dBm): 12dBi high-gain antenna + receiving diversity technology supported by the router is required to achieve a stable connection

　　When the router supports LTE Cat.6 and above standards (receiving sensitivity is increased to - 115dBm), it can be connected in the extreme environment of - 115dBm with a 10dBi antenna, which extends the coverage range by 5dB compared to Cat.4 routers (-110dBm).

　　Compatibility test and troubleshooting

　　Quick verification method

　　Signal strength test: After connecting, check the RSRP value through the router management interface. If it is ≥8dB higher than the original antenna, it is basically compatible

　　Rate test: Perform Speedtest test at the same location. If the download rate is increased by ≥30%, it means the match is good

　　Stability test: Continuously ping the gateway (1 hour), the packet loss rate is ≤1% and the jitter is ≤10ms to pass

　　Common compatibility issues and solutions

　　Loose interface: The signal is sometimes strong and sometimes weak. The solution is to replace the interface with a loose gasket (such as an SMA connector with an O-ring)

　　Band mismatch: There is no signal in a certain band. You need to replace the full-band antenna or turn off the unsupported band through the router settings

　　Power overload: Frequent disconnection, which can be solved by reducing the router's transmit power (adjusted to 20dBm in the advanced settings) or replacing a low-gain antenna

　　Impedance mismatch: The standing wave ratio is too high (>2.0), and a 50Ω matching network can be connected in series (professional debugging is required)

　　Adaptation recommendations for mainstream routers and antennas

　　Consumer-grade router adaptation

　　Huawei B310/B315 (SMA interface, supports B1/B3/B5/B8): Recommended 8dBi SMA interface omnidirectional fiberglass antenna (such as TP-Link TL-ANT2408CL), which can increase the B8 band (900MHz) signal by 12dB in rural areas

　　Xiaomi 4G router (SMA interface, supports B3/B8): With 6dBi dual-polarized antenna (±45°), MIMO throughput is increased by 40%, and 4K video loading time is reduced from 8 seconds to 3 seconds

　　Industrial-grade CPE adaptation

　　ZTE MC801A (N-type interface, supports B1/B3/B5/B7/B8/B20): Adapted with 10dBi directional fiberglass antenna (such as Huawei ANT350), after aligning with the base station direction, the download rate at 10 kilometers is increased from 5Mbps to 12Mbps

　　Nokia FastMile 5G Gateway (N-type interface, compatible 4G B1/B3/B7/B20): With dual-port 12dBi antenna, the edge rate is increased by 50% through MIMO technology to meet the VPN connection requirements of remote office. The compatibility of 4G fiberglass antenna and router is not a simple "can be connected", but requires precise matching in three dimensions: physical interface, electrical parameters, and application scenarios. When purchasing, users should first record the interface type, supported frequency band and power parameters of the router, and then screen it according to the corresponding indicators of the antenna. If necessary, verify it through the compatibility list provided by the merchant (such as Huawei's official certified antenna list) to maximize the signal enhancement effect.