1. Confirm Operating Frequency Band (Primary Criterion)
The frequency band serves as the fundamental basis for antenna selection. An antenna delivers optimal radiation and reception performance only within its specified frequency range. Mismatched frequency bands will result in severe signal attenuation, high transmission loss and unstable communication.
First, the antenna’s nominal frequency range must fully cover the operational frequencies of the device, with clear differentiation between single-band, multi-band and wideband requirements. Second, regional spectrum compliance standards shall be strictly observed for overseas products to avoid compatibility risks in target markets. Third, appropriate frequency bandwidth margin is reserved to accommodate minor frequency fluctuations and ensure consistent communication stability under complex operating conditions.
2. Select Radiation Mode Based on Application Scenarios
Radiation patterns are determined by coverage requirements and transmission distances, mainly divided into omnidirectional and directional antennas.
2.1 Omnidirectional Antennas
Omnidirectional antennas provide uniform 360° horizontal signal coverage with a typical gain of 2–5 dBi and moderate transmission distance. They are ideal for devices requiring all-directional signal transceiving, including consumer electronics, indoor terminals and IoT devices, which feature multi-directional and non-fixed communication demands.
2.2 Directional Antennas
Directional antennas concentrate signal energy in a single direction, featuring narrow beamwidth, high gain (10–15 dBi), long transmission distance and strong anti-interference capability. They are widely applied in point-to-point long-distance transmission, base station docking, industrial fixed-point communication and outdoor data transmission scenarios, effectively reducing invalid signal radiation and co-frequency interference.
3. Determine Antenna Form Based on Structural and Installation Constraints
Antenna form factors are selected according to internal space layout, product appearance and installation conditions to balance performance, aesthetics and installation feasibility.
3.1 Built-in Antennas
Built-in antennas include PCB, FPC, LDS and PIFA antennas. They require no external installation and maintain product integrity, making them suitable for compact and lightweight devices. PCB antennas feature low mass-production cost and high consistency for general commercial products. FPC antennas offer high flexibility for irregular structural designs and are commonly used in mid-to-high-end equipment. LDS antennas deliver high space utilization and stable performance for premium intelligent devices. It is noteworthy that built-in antennas are susceptible to interference from metal shells, batteries and PCBs, requiring reserved clearance areas for optimal performance.
3.2 External Antennas
External antennas include rod antennas, suction cup antennas and high-gain directional antennas. With flexible installation, low susceptibility to internal device interference and stable signal performance, they support adjustable gain and are widely adopted in industrial equipment, outdoor communication terminals and high-reliability commercial devices. The main limitation is additional external space occupation.
4. Performance Calibration via Core Technical Parameters
Parameter verification is essential to ensure compliant and reliable communication performance.
Gain: Higher gain supports longer transmission distance yet narrower signal coverage. Low-gain antennas are applied for short-distance full-scenario coverage, while high-gain options are adopted for long-distance directional transmission to avoid coverage blind spots.
VSWR: A VSWR value of 1.5 or below is preferred. Lower VSWR indicates better impedance matching, minimized signal reflection loss and higher communication stability.
Polarization: Vertical polarization is commonly used for short-distance civilian communication, while dual-polarization antennas are applied in long-distance and anti-interference scenarios to improve signal reception tolerance.
Impedance Matching: The industry-standard 50Ω impedance must be consistent with the RF port impedance of the device to avoid signal attenuation and power loss caused by impedance mismatch.
5. Environmental and Operational Adaptability
Indoor devices prioritize compact size, low interference and high compatibility without strict environmental protection requirements. Outdoor and industrial devices adopt industrial-grade antennas with waterproof, dustproof, high and low temperature resistance and anti-aging properties to adapt to harsh working conditions. Devices operating in complex electromagnetic environments deploy shielded or directional antennas to mitigate external electromagnetic interference.
6. Cost and Mass Production Adaptability
For mass-produced general products, mature and cost-effective PCB and standard rod antennas are prioritized to ensure batch consistency. For mid-to-high-end customized products, FPC and LDS antennas are preferred to balance structural space, appearance and performance. For special-scenario equipment, customized wideband, high-gain and special-structure antennas are configured to prioritize operational performance and long-term stability.
7. Final Verification Criteria for Antenna Selection
1. Full matching of frequency band, impedance and polarization with device specifications;
2. Compatible antenna size and form factor with product installation space and design;
3. Matched gain and radiation pattern with actual transmission distance and coverage scenarios;
4. Compliant environmental protection grade with practical operating conditions;
5. Optimized impedance matching and actual testing to further enhance overall antenna performance.