In the field of electromagnetic radiation devices, RF antennas and microwave antennas are often confused, but there are actually fundamental differences. This article conducts professional analysis from three dimensions: frequency band definition, design principle, and manufacturing process, especially combining key technologies such as vacuum brazing.
RF MISO Vacuum Brazing Furnace
1. Frequency band range and physical characteristics
RF antenna:
The operating frequency band is 300 kHz - 300 GHz, covering medium wave broadcasting (535-1605 kHz) to millimeter wave (30-300 GHz), but the core applications are concentrated in < 6 GHz (such as 4G LTE, WiFi 6). The wavelength is longer (centimeter to meter level), the structure is mainly dipole and whip antenna, and the sensitivity to tolerance is low (±1% wavelength is acceptable).
Microwave antenna:
Specifically 1 GHz - 300 GHz (microwave to millimeter wave), typical application frequency bands such as X-band (8-12 GHz) and Ka-band (26.5-40 GHz). Short wavelength (millimeter level) requirements:
✅ Submillimeter level processing accuracy (tolerance ≤±0.01λ)
✅ Strict surface roughness control (< 3μm Ra)
✅ Low-loss dielectric substrate (ε<sub>r</sub>≤2.2, tanδ≤0.001)
2. The watershed of manufacturing technology
The performance of microwave antennas is highly dependent on high-end manufacturing technology:
| Technology | RF Antenna | Microwave Antenna |
| Connection technology | Soldering/Screw fastening | Vacuum Brazed |
| Typical Suppliers | General Electronics Factory | Brazing Companies like Solar Atmospheres |
| Welding requirements | Conductive connection | Zero oxygen penetration, grain structure reorganization |
| Key Metrics | On-resistance <50mΩ | Thermal expansion coefficient matching (ΔCTE<1ppm/℃) |
The core value of vacuum brazing in microwave antennas:
1. Oxidation-free connection: brazing in a 10<sup>-5</sup> Torr vacuum environment to avoid oxidation of Cu/Al alloys and maintain conductivity >98% IACS
2. Thermal stress elimination: gradient heating to above the liquidus of the brazing material (e.g. BAISi-4 alloy, liquidus 575℃) to eliminate microcracks
3. Deformation control: overall deformation <0.1mm/m to ensure millimeter wave phase consistency
3. Comparison of electrical performance and application scenarios
Radiation characteristics:
1.RF antenna: mainly omnidirectional radiation, gain ≤10 dBi
2.Microwave antenna: highly directional (beam width 1°-10°), gain 15-50 dBi
Typical applications:
| RF Antenna | Microwave Antenna |
| FM radio tower | Phased Array Radar T/R Components |
| IoT Sensors | Satellite communication feed |
| RFID Tags | 5G mmWave AAU |
4. Test verification differences
RF antenna:
- Focus: Impedance matching (VSWR < 2.0)
- Method: Vector network analyzer frequency sweep
Microwave antenna:
- Focus: Radiation pattern/phase consistency
- Method: Near field scanning (accuracy λ/50), compact field test
Conclusion: RF antennas are the cornerstone of generalized wireless connectivity, while microwave antennas are the core of high-frequency and high-precision systems. The watershed between the two is:
1. The increase in frequency leads to a shortened wavelength, triggering a paradigm shift in design
2. Manufacturing process transition - microwave antennas rely on cutting-edge technologies such as vacuum brazing to ensure performance
3. Test complexity grows exponentially
Vacuum brazing solutions provided by professional brazing companies such as Solar Atmospheres have become a key guarantee for the reliability of millimeter wave systems. As 6G expands to the terahertz frequency band, the value of this process will become more prominent.
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Post time: May-30-2025
