Microwave PCB

Teflon microwave circuit board

Application Fields of High Frequency Microwave PCB

1. Mobile communication devices and intelligent lighting systems
2. RF functional modules such as power amplifiers and low-noise amplifiers
3. Passive microwave components: power dividers, couplers, duplexers, high-frequency filters
4. Automotive anti-collision radar, satellite navigation, wireless radio systems; high-frequency design has become the core development trend of modern electronic products

Classification of High Frequency Microwave PCB

1. Ceramic-filled thermoset substrate

2. PTFE (Polytetrafluoroethylene) / Teflon PCB

• Rogers: RO3000 series, RT/duroid series, TMM series
• Arlon: AD/AR series, Isoclad series, Cuclad series
• Taconic: RF series, TLX series, TLY series
• Domestic microwave-grade substrates: F4B, F4BM, F4BK, TP-2

Core Processing Specifications for PTFE PCB

1. Cutting: Protective films are reserved throughout processing to prevent surface scratches and indentations.
2. Drilling:
   Use brand-new 130° standard drill bits with single-stack processing; control pressing pressure at 40psi. Adopt aluminum cover plates and 1mm buffer gaskets for clamping. Clear hole dust with air blowing after drilling. Match precise drilling parameters: high rotating speed, low feed rate and low retraction speed for micro holes.
3. Hole Treatment: Plasma treatment or sodium naphthalene activation is mandatory to enhance hole wall adhesion for reliable copper metallization.
4. PTH Process: Control micro-etch depth at 20 micro-inches; secondary copper deposition is available to fix poor hole plating.
5. Solder Mask: Acid cleaning replaces mechanical grinding for pre-treatment. Pre-bake boards at 90°C for 30 minutes before ink coating. Conduct segmented curing at 80°C, 100°C and 150°C (30 minutes for each stage). Rework is allowed for oil leakage and coating defects.
6. Profiling: Lay blank paper on the board surface and clamp with 1.0mm FR-4 upper and lower pads to reduce burrs and structural damage.

Standard Process Flow

1. NPTH PTFE PCB:
   Material cutting → Drilling → Dry film → Inspection → Etching → Solder mask → Legend printing → Surface finishing → Profiling → Electrical testing → Final inspection → Packaging
2. PTH PTFE PCB:
   Material cutting → Drilling → Hole activation → Electroless copper plating → Panel electroplating → Dry film → Etching → Solder mask → Legend printing → Surface finishing → Profiling → Testing → Delivery

Core Processing Difficulties

1. Low hole copper adhesion: The inert PTFE hole wall leads to unstable electroplating and easy copper peeling.
2. Strict precision control: Difficult management of etching consistency, line width tolerance and micro pit defects.
3. Solder mask limitation: Poor ink adhesion often causes blistering and peeling on Teflon surfaces.
4. High surface protection requirements: The soft substrate is easily scratched, requiring full-process anti-damage measures.

Importance of Professional Microwave PCB Manufacturers

Advantages of Maxipcb for RF & Microwave PCB Manufacturing

• Diverse material selection: Support imported and domestic high-frequency substrates to balance performance and cost.
• Complex process capability: Mature mass production of mixed dielectric lamination, ceramic substrate PCB and multi-layer high-frequency boards.
• Full technical support: Pre-production design review, risk assessment and optimization; strict control of impedance, line width and hole quality during production.
• Integrated testing services: Comprehensive electrical and high-frequency performance testing to reduce customer verification costs.
• Customized solution: Provide alternative processes for special design requirements to meet delivery and quality demands.