Introduction to Connector

Chapter 1: Connector Fundamentals

What is a Connector?

A connector is a separable component in an electronic system that enables electrical connection and disconnection between circuits, cables, devices, or subsystems. A complete connector system typically consists of aplug (male)and areceptacle/jack (female), which establish electrical continuity through contact terminals.

Connectors serve as the "nervous system" of modern electronics. From consumer electronics and automotive to industrial automation, aerospace, and military defense, virtually all electronic devices rely on connectors. Statistics show that a modern electric vehicle uses over 500 connectors, while a commercial aircraft may contain more than 100,000 connector interfaces.

Basic Connector Structure

Regardless of connector type, the core structure can be broken down into the following key components:

1. Contact Terminal:

The core conductive element, typically made from copper alloys (phosphor bronze, beryllium copper) with surface plating (gold, tin, or silver) to reduce contact resistance and improve oxidation resistance.

Insulator / Housing:Holds terminals in position and prevents short circuits between adjacent contacts. Common materials include LCP (Liquid Crystal Polymer), PBT, and PA66 engineering plastics.

2. Shell / Housing:

Provides mechanical protection, EMI shielding, and polarization. Metal shells are typically made from zinc alloy, aluminum alloy, or stainless steel.

3. Locking Mechanism:

Ensures the connector remains mated under vibration and stress. Common types include latch, threaded, push-pull, and screw-lock designs.

4. Sealing / Gasket:

Used in waterproof connectors, typically silicone or rubber O-rings or gaskets for IP-rated protection.

Key Electrical Parameters

Parameter	Symbol	Definition	Typical Range
Contact Resistance	Rc	Resistance at the contact interface; lower is better	0.1 ~ 50 mΩ
Insulation Resistance	Ri	Resistance between adjacent terminals; higher is better	10³ ~ 10⁶ MΩ
Withstanding Voltage	DWV	Maximum voltage without dielectric breakdown	100V ~ 5000V
Rated Current	Ir	Maximum continuous current for safe operation	0.5A ~ 1000A+
Characteristic Impedance	Z₀	Voltage-to-current ratio for high-frequency connectors (Ω)	50Ω / 75Ω
Insertion Loss	IL	Signal attenuation through connector (dB)	0.01 ~ 3 dB
Voltage Standing Wave Ratio	VSWR	Measure of impedance matching; closer to 1 is better	1.01 ~ 1.5

Core Mechanical Parameters

Parameter	Definition	Importance
Insertion Force	Force required to mate the plug into the receptacle	Affects assembly efficiency and operator fatigue
Extraction Force	Force required to unmated the connector	Balance between serviceability and retention
Mating Cycles (Durability)	Number of mating/unmating operations	Consumer: 500; Military: 5000+
Terminal Retention Force	Force holding terminal in the housing	Prevents terminal pull-out from cable stress
Polarization / Keying	Prevention of incorrect mating orientation	Avoids damage from mis-insertion

Three Major Connector Categories

Based on application and technical characteristics, connectors can be classified into three main categories, each with unique design priorities:

Chapter 2: High-Frequency Connectors (RF Connectors)

Overview of High-Frequency Connectors

High-frequency connectors, also known as RF (Radio Frequency) connectors, are specifically designed for transmitting high-frequency electromagnetic signals (typically above 100 MHz). Unlike general low-frequency connectors, RF connectors must account for transmission line theory— including characteristic impedance, skin effect, and electromagnetic wave reflection.

As signal frequency increases, current tends to concentrate on the conductor surface (skin effect), reducing effective cross-section and increasing resistance. Meanwhile, any impedance discontinuity causes signal reflections, forming standing waves that reduce transmission efficiency and may damage the signal source. Therefore, the core design goal of RF connectors is tomaintain constant characteristic impedance across the entire frequency band (typically 50Ω or 75Ω).

Coaxial Connector Structure and Principles

The vast majority of RF connectors use a coaxial structure consisting of four concentric layers. This design effectively confines electromagnetic fields within the dielectric layer, preventing radiation loss and external interference:

1. Inner Conductor:

The core signal pathway, typically silver-plated or gold-plated copper wire/tube.

2. Dielectric Layer:

Supports the inner conductor and maintains precise spacing from the outer shield. Common materials include PTFE (Teflon), PE, or air dielectric.

3. Outer Shield / Conductor:

Provides electromagnetic shielding and the ground return path, typically braided copper mesh or copper foil.

4. Insulating Jacket:

The outermost mechanical protection layer, typically PVC or TPE material.

Common High-Frequency Connector Types

Based on size, frequency range, and application domain, the industry has established standardized RF connector families. The following are the most common types used in engineering practice:

1. BNC Connector (Bayonet Neill-Concelman

BNC is the most common low-to-medium frequency RF connector, featuring a bayonet-lock coupling mechanism for quick connect/disconnect. Available in 50Ω and 75Ω versions. Due to its relatively large physical size, the maximum operating frequency is limited to approximately 4 GHz (recommended use below 2 GHz). BNC is widely used in test instruments (oscilloscopes, signal generators), surveillance systems (CCTV), and low-frequency communication equipment. Advantages include low cost and quick connection; disadvantages include standing wave issues at higher frequencies and inferior shielding compared to threaded connectors.

2. SMA Connector (SubMiniature version A)

SMA is the most widely used miniature high-frequency connector, featuring a 1/4-inch 36-thread coupling mechanism. Standard SMA operates up to 18 GHz; precision versions (3.5mm, 2.92mm) can reach 26.5 GHz and 40 GHz respectively. SMA is approximately 1/3 the size of BNC, suitable for space-constrained applications. 50Ω and 75Ω versions have identical external dimensions but different center pin sizes —they are NOT interchangeable and mixing them will damage the connector. SMA is widely used in microwave communications, 5G base stations, satellite equipment, radar systems, and laboratory test equipment. Torque control is critical when using SMA (typically 7-10 in-lb); over tightening can deform the dielectric layer and affect impedance matching.

3. N-Type Connector (Named after Paul Neill)

The N-type connector is a medium-sized threaded RF connector invented by Paul Neill at Bell Labs in the 1940s — one of the earliest connectors capable of supporting microwave frequencies. Standard N-type operates up to 18 GHz; precision versions reach 26.5 GHz. N-type connectors offer significantly higher power handling than SMA — approximately 1000W CW at 1 GHz — making them ideal for base stations, broadcast transmitters, and high-power radar systems. N-type connectors are available in 50Ω and 75Ω versions, distinguishable by center pin diameter and dielectric color.

4. TNC Connector (Threaded Neill-Concelman)

TNC is essentially a BNC connector with the bayonet coupling replaced by a threaded coupling, providing better shielding and lower VSWR, operating up to 11 GHz (some precision versions reach 18 GHz). TNC is more reliable than BNC in vibration environments and is commonly used in mobile communications, avionics, and military equipment. Reverse-polarity TNC (RP-TNC) is commonly used in Wi-Fi equipment to prevent the use of standard antennas.

5. Precision Connectors: 3.5mm / 2.92mm / 2.4mm / 1.85mm / 1.0mm

These precision-grade coaxial connectors use air dielectric (or minimal dielectric support) for precision measurements at millimeter-wave frequencies. 3.5mm reaches 26.5 GHz, 2.92mm (also called K-type) reaches 40 GHz, 2.4mm reaches 50 GHz, 1.85mm (V-type) reaches 67 GHz, and the latest 1.0mm connector extends to 110 GHz. The outer conductor inner diameter matches the name (in mm), and center pin dimensions are strictly standardized for mating compatibility. These connectors are expensive and require extreme cleanliness and precise torque, primarily used in network analyzers, spectrum analyzers, and other high-end test equipment.

6. FAKRA Connector

FAKRA (FAchKReis Automobile) is an RF connector standard specifically designed for the automotive industry, based on the SMB connector but with a plastic housing and color-coding system. FAKRA operates up to 6 GHz and is primarily used for in-vehicle GPS, 4G/5G antennas, V2X communications, and ADAS radar systems. Different FAKRA housing colors correspond to different applications (e.g., purple = GPS, blue = GSM, green = TV) to prevent mis-mating. FAKRA connectors must pass stringent automotive-grade environmental testing (vibration, temperature cycling, waterproof IP6K9K).

Key RF Connector Performance Parameters

Parameter	Description	Test Method	Typical Requirement
Characteristic Impedance Z₀	Equivalent resistance presented to high-frequency signals	TDR (Time Domain Reflectometer)	50Ω ± 2Ω
VSWR	Measure of impedance matching; closer to 1 is better	Network Analyzer	< 1.2:1
Insertion Loss (IL)	Signal energy loss through the connector (dB)	Network Analyzer S21	< 0.2 dB @ 18GHz
Return Loss (RL)	Ratio of reflected to incident signal power (dB)	Network Analyzer S11	> 20 dB
Frequency Range	Maximum usable frequency	-	Model dependent
Power Capacity	Maximum RF power handling (W)	Power load test	Varies by model/frequency

Impedance Matching and VSWR Principles

In high-frequency systems, impedance matching is the key to efficient signal transmission. When source impedance (Zs), transmission line characteristic impedance (Z₀), and load impedance (ZL) are all equal, this is called a "matched state" with no signal reflection and 100% energy delivered to the load. If impedance is mismatched, some signal is reflected back to the source, creating standing waves.

VSWR (Voltage Standing Wave Ratio) measures the degree of matching. VSWR = 1 indicates perfect match; VSWR = 1.5 means ~4% reflected power; VSWR > 2 means over 11% reflected power, which may damage power amplifiers. High-quality RF connectors should maintain VSWR < 1.2 across the full frequency band.

Chapter 3: High-Current Connectors (Power Connectors)

Overview of High-Current Connectors

High-current connectors are specifically designed for high-power energy transmission, typically referring to connectors with a rated current exceeding 10 amperes. These connectors are widely used in electric vehicles, energy storage systems, industrial automation, power distribution equipment, rail transportation, and renewable energy (solar, wind).

The core technical challenge for high-current connectors is Joule heat management. According to Joule's law P = I²R, when current flows through contact resistance, heat is generated — doubling the current quadruples the heat. If this heat cannot be effectively dissipated, the contact temperature continues to rise, potentially leading to metal annealing, reduced contact pressure, further increased resistance, and a vicious cycle that ultimately causes connector burnout or even fire. Therefore, the primary design goals are to minimize contact resistance and maximize heat dissipation capability.

1. Contact Resistance Minimization

Contact resistance is the core factor determining connector temperature rise. Methods to reduce contact resistance include:

High-conductivity materials:Contact springs use beryllium copper (C17200) or high-copper alloys; housings use brass (C36000) or pure copper to maximize conductive cross-section.

Surface plating:Contact surfaces plated with silver (highest conductivity) or gold (best oxidation resistance), typically 3-30μm thickness. Silver plating is preferred for high-current applications.

Increased contact area:Multi-point contact designs or larger terminal cross-sections; some designs use Eye-of-the-Needle press-fit zones to reduce overall resistance.

Adequate contact force:Contact pressure directly affects the actual metal-to-metal contact area. Insufficient pressure causes poor contact; excessive pressure accelerates metal fatigue and wear. Designers must balance contact resistance, insertion force, and longevity.

2. Thermal Management Design

Effective thermal management ensures reliable high-current connector operation:

Increased conductor cross-section:As a rule of thumb, copper conductors safely carry approximately 5-10A/mm² (depending on cooling conditions). Terminal and cable cross-sections must be adequately sized.

High-temperature materials:Insulation materials must have high heat deflection temperature (HDT). Common materials include PA66+GF (105°C), PBT+GF (140°C), and LCP (220°C+).

Enhanced heat dissipation paths:Heat dissipation through metal housings, forced air cooling, or liquid cooling designs to reduce connector temperature rise.

Temperature monitoring:Premium high-current connectors integrate temperature sensors (e.g., NTC thermistors) that trigger protection when temperature exceeds thresholds.

3. Mechanical Stability

High-current connectors typically carry heavy cables, and cable weight and bending stresses impose higher mechanical requirements:

Cable clamping and strain relief:Metal cable glands or strain relief boots prevent cable pull forces from reaching the terminals.

Anti-loosening design:High-current connectors commonly use screw-locking, lever-locking, or bayonet-locking to ensure stable contact in vibration environments.

Polarization and keying:Different keying positions or color coding prevent mis-mating, especially critical in three-phase AC applications where incorrect phase sequencing can damage equipment.

Common High-Current Connector Types

1. Heavy Duty Connectors (Industrial Multipole)

Heavy duty connectors (also called rectangular industrial connectors) offer a modular high-current connection solution. The typical representative is the Harting Han® series and TE Connectivity's HD series. Their key feature is combining multiple modules (power, signal, data, pneumatic) within a single metal frame for integrated transmission.

A single power module can carry up to 200A (e.g., Han® HPR series), while standard modules typically handle 16A or 40A. Heavy duty connectors use metal housings providing IP65/IP67 protection and EMC shielding, secured by screws or levers. They are widely used in machine tools, robotics, automated production lines, and rail transportation.

2. Anderson Powerpole® Series

Anderson Powerpole® is a modular, genderless high-current DC connector widely used in amateur radio, electric models, UPS systems, and EV charging. Its core feature is that the same housing can serve as either plug or receptacle through mirrored arrangement. Single-pole versions handle currents from 15A to 350A, with housing colors indicating different current and voltage ratings (red = 15A/45A, gray = 75A, black = 130A, etc.). Contacts use flat-milled copper with silver plating and crimp termination (AWG 20 to AWG 1/0).

3. Circular Power Connectors

Circular power connectors dominate in aerospace and military applications, with typical representatives including the MIL-DTL-38999 and MIL-C-26482 series. These connectors use high-density circular contact arrangements that can simultaneously transmit power and signals, with individual contacts handling 200A+ (e.g., size 8 contacts). Coupling mechanisms include threaded, bayonet, and push-pull types, offering excellent vibration and shock resistance. Military-spec circular connectors must pass rigorous MIL-STD testing including salt spray (96+ hours), sand/dust, immersion, and thermal shock.

4. Terminal Blocks and Busbar Connectors

Terminal blocks are the most basic high-current connection solution, suitable for fixed installations in distribution cabinets and control boxes. High-current terminal blocks use screw-clamp or spring-clamp wire fixation, with rated currents from 10A to 1000A. Busbar connectors are used to connect copper or aluminum busbars, commonly found in switchgear, inverters, and battery management systems (BMS). High-quality terminal blocks use copper alloy bodies with tin plating, achieving contact resistance as low as 0.01mΩ.

5. Sealed Automotive Connectors

EV high-current connectors must simultaneously meet high current-carrying, waterproof/dustproof (IP6K9K), vibration resistance, and miniaturization requirements. Typical representatives include TE Connectivity's Superseal series, Amphenol's HVSL series (high-voltage interlock connectors), and Yazaki connector products. These connectors typically use two-stage locking (CPA — Connector Position Assurance) and built-in HVIL (High Voltage Interlock Loop) safety circuits to ensure power is cut when high-voltage connectors are not fully mated, preventing live mating arcs.

6. Energy Storage / EV Charging Connectors

EV charging interfaces are divided into AC slow charging (Type 1/Type 2/GB/T) and DC fast charging (CCS/CHAdeMO/GB/T). DC fast charging connectors must carry up to 500A (liquid-cooled charging guns can reach 600A). Contact terminals typically use silver alloy plating, and charging guns incorporate temperature sensors to monitor terminal temperature rise. Tesla's NACS (North American Charging Standard) connector is compact yet capable of handling up to 1000V/500A and has become the dominant standard in the North American market.

High-Current Connector Key Specifications

Parameter	Description	Typical Range	Design Impact
Rated Current (Ir)	Maximum current for continuous safe operation	10A ~ 1000A+	Determines terminal cross-section and thermal design
Rated Voltage (Ur)	Maximum continuous operating voltage	12V ~ 1500V DC	Determines insulation spacing and material selection
Contact Resistance	Resistance at the terminal contact interface	0.01 ~ 5 mΩ	Directly affects temperature rise and power loss
Temperature Rise	Temperature increase at full load	< 30K ~ 50K	Determines insulation material temperature rating
Protection Rating (IP)	Dust and water resistance capability	IP20 ~ IP6K9K	Determines sealing design complexity
Cable Cross-Section	Compatible wire gauge	AWG 20 ~ 1000 kcmil	Must match terminal crimp barrel size
Flammability Rating	UL94 fire safety rating	V-2 / V-1 / V-0 / 5VA	Determines plastic material selection

Connector Temperature Rise and Derating

The actual current-carrying capacity of a connector decreases as ambient temperature increases — this is called "derating." A connector's rated current is typically measured at 40°C ambient; if the actual environment is hotter, the operating current must be reduced for safety.

High temperature damage to connectors includes: metal stress relaxation leading to reduced contact force, insulation aging and embrittlement, and plating diffusion forming intermetallic compounds (IMC) that increase contact resistance. Therefore, design should incorporate adequate derating margins — generally keeping operating current at 70-80% of rated current in high-temperature environments.

Chapter 4: High-Precision Connectors (Fine-Pitch Connectors)

Overview of High-Precision Connectors

High-precision connectors (also called fine-pitch or micro-pitch connectors) refer to connectors with contact center spacing (pitch) of 1.0mm or less, with the most advanced products reaching 0.2mm pitch. These connectors are key enablers of the lightweight and miniaturization trends in modern electronics, widely used in smartphones, tablets, wearable devices, medical electronics, drones, servers, and military/aerospace equipment.

High-precision connectors face two core technical challenges:micro-precision manufacturing and signal integrity assurance. As terminal pitch decreases, the requirements for injection molding, stamping, and plating process precision become extremely demanding. At the same time, crosstalk between adjacent terminals, impedance control, and EMI become more severe. Additionally, micro-pitch connectors are extremely delicate to handle, and improper mating can easily deform or damage terminals, making polarization design and ease of operation equally important.

Core Technologies for High-Precision Connectors

1. Precision Stamping and Micro-Machining

High-precision connector terminals can be narrower than 0.1mm, requiring stamping die precision at the micrometer level (±1μm or better). Terminal materials typically use high-strength copper alloys:

Phosphor Bronze (C51000/C52100):Lower cost, moderate elasticity, suitable for static contact applications.

Beryllium Copper (C17200/C17510):Excellent elasticity and long fatigue life, suitable for frequent mating applications, but higher cost.

Copper-Nickel-Silicon Alloy (C7025/C7035):A balanced choice with good elasticity and conductivity, the mainstream material for modern high-precision connectors.

Titanium Copper (C19900):Ultra-high strength, used for sub-0.35mm ultra-fine pitch products.

For plating, contact areas typically use selective gold plating (0.03-0.75μm Au over a nickel underlayer), while solder tail areas are plated with tin or tin-lead for solderability. Selective plating significantly reduces cost since gold is expensive and only needs to cover actual contact areas.

2. High-Speed Signal Integrity Design

When signal transmission rates exceed 1 Gbps, connectors must be designed as controlled-impedance transmission lines. Key factors affecting signal integrity include:

Characteristic Impedance Control:By adjusting terminal width, spacing, plastic dielectric constant, and reference ground planes, the differential impedance is controlled to target values of 100Ω (USB/PCIe) or 85Ω (DDR), typically with ±10% tolerance.

Crosstalk Suppression:Electromagnetic coupling between adjacent signal lines causes crosstalk. Mitigation methods include adding ground pins, differential pair routing, increasing signal-to-signal spacing, or adding shielding plates between terminals.

Insertion Loss and Return Loss:Geometric discontinuities in connectors (bends, cross-section changes) cause signal reflection and attenuation. Optimized terminal shapes, reduced stub lengths, and low-loss plastic materials (LCP, PPS) improve high-frequency performance.

EMI/EMC:Metal shielding shells effectively block electromagnetic radiation. High-speed connectors (USB Type-C, HDMI) typically feature metal housings with multi-point grounding.

3. Ultra-Thin Stacking and High-Density Layout

In extremely space-constrained applications like smartphones, board-to-board connector stacking heights have been reduced from the traditional 5-10mm to 0.6mm or even less. This requires ultra-thin connector bodies while maintaining adequate terminal retention force and mating reliability.

To achieve ultra-thin designs, manufacturers employ: LCP (Liquid Crystal Polymer) thin-wall injection molding (wall thickness down to 0.05mm), precision etching (rather than traditional stamping) for metal terminals, and dual-row or staggered layouts to increase terminal density per unit area.

Common High-Precision Connector Types

1. Board-to-Board Connectors (BTB)

Board-to-board connectors are used for vertical interconnection between parallel PCBs and are the most common type of high-precision connector. Based on stacking orientation, they can be classified as:

Vertical Stacking (Mezzanine/Stacking):Two PCBs stacked parallel with the connector mounted vertically. Pitch ranges from 0.35mm to 2.54mm, with stacking heights from 0.6mm to over 20mm. Representative products include TE Free Height series, Hirose DF40 series, and Amphenol Nanominiature series.

Coplanar Connection:Two PCBs on the same plane connected via card-edge or side-entry connectors. Commonly used for expansion cards and motherboard connections.

Backplane/Midplane Connection:Used in server and telecom backplane systems, connectors must simultaneously support high-speed differential signals (PCIe, SAS) and power transmission, typically with 0.8mm or 1.0mm pitch. Representative products include Molex Impact series and TE Z-PACK series.

2. FPC/FFC Connectors (Flexible Circuit Connectors)

FPC (Flexible Printed Circuit) and FFC (Flexible Flat Cable) connectors connect flexible cables to rigid PCBs, making them the preferred solution for foldable phones, camera modules, and display panels. FPC connectors typically use flip-lock or slider designs to hold the cable, with pitch specifications of 0.2mm, 0.3mm, 0.5mm, and 1.0mm.

When selecting FPC connectors, confirm: cable pitch, cable thickness (typically 0.2mm or 0.3mm), contact type (top/bottom/dual contact), and whether ZIF (Zero Insertion Force) is required. ZIF connectors use a flip mechanism to open contacts, allowing the cable to be inserted before closing the latch, greatly reducing cable damage risk.

3. Wire-to-Board Connectors (WTB)

Wire-to-board connectors connect wires/cables to PCBs and are the most prevalent connector type in electronics. High-precision WTB connectors use crimp terminals joined to conductors using a dedicated crimping tool. Common specifications include JST SH (1.0mm), GH (1.25mm), ZH (1.5mm), PH (2.0mm) series, and Molex PicoBlade (1.25mm), SlimStack series, etc.

Crimp quality directly affects connection reliability. A good crimp should: fully enclose the conductor with the crimp barrel, have no copper strands protruding, show a symmetrical hexagonal cross-section, and meet specified pull-force requirements. Crimp height is a critical control parameter requiring dedicated crimping tools and positioners for consistency.

4. I/O Connectors

I/O connectors are the interfaces between devices and the external world. Modern high-precision I/O connectors must simultaneously support high-speed data, power delivery, and multi-function integration:

USB Type-C:24-pin full-feature connector supporting USB4 (40 Gbps), PD charging (up to 240W), DisplayPort Alt Mode, and audio. Reversible plug orientation, compact size (8.34mm × 2.56mm), now the standard interface for consumer electronics.

HDMI / DisplayPort:For video signal transmission, supporting 4K/8K resolution. High-precision versions use micro contacts and full metal shield housings.

Thunderbolt:Physically compatible with USB Type-C, supports bidirectional transmission up to 120 Gbps, used in high-end laptops and external GPU docks.

5. Micro-Circular Connectors

In aerospace and military applications where space and weight are severely constrained, high-density micro-circular connectors have been developed. Representative products include MIL-DTL-38999 series (high-density versions up to 128 contacts), Amphenol Nanominiature series (0.635mm pitch), and Souriau MicroComp series. These connectors use aluminum or titanium alloy housings weighing only 1/5 to 1/10 of traditional connectors, while meeting stringent MIL-STD environmental requirements.

6. Pogo Pin / Test Probe Connectors

Pogo pins are single-ended spring-loaded contacts that use an internal spring to provide contact force, widely used in PCB test fixtures (ICT/FCT), programming sockets, and temporary connections. Pogo pin diameters can be as small as 0.2mm, with pitch down to 0.35mm, and lifespans ranging from 10,000 to 1,000,000 cycles. When selecting Pogo pins, consider: working travel, spring force, contact resistance, and plating material (gold or rhodium).

Terminal Crimping and Termination Technologies

The termination method of high-precision connectors directly affects connection quality and long-term reliability. The following are the five main termination technologies:

1. Crimp:

Uses a crimping tool to compress the terminal barrel, clamping the conductor copper strands. Crimping is the most common high-volume production method — fast and reliable — but requires dedicated tooling and precise crimp height control.

2. Solder:

Uses molten solder to connect wires or connector solder tails to PCB pads. Suitable for low-volume or repair work, but long-term reliability is affected by solder fatigue and thermal cycling.

3. SMT (Surface Mount Technology):

Connectors are directly soldered to the PCB surface, suitable for automated production and double-sided layouts. SMT connectors are sensitive to pad design and reflow temperature profiles, requiring strict adherence to manufacturer specifications.

4. THT (Through-Hole Technology / DIP):

Connector pins pass through PCB holes for wave soldering or hand soldering. THT provides higher mechanical strength than SMT, suitable for applications requiring greater mating/unmating force.

5. IDC (Insulation Displacement Connection):

Uses V-shaped blades to pierce flat cable insulation and clamp the conductor. IDC is suitable for quick termination of flat cables without stripping, commonly used in FFC connectors and some WTB applications.

Core Characteristics Comparison

Comparison Item	RF / High-Frequency Connector	High-Current / Power Connector	High-Precision / Fine-Pitch Connector
Core Function	RF / High-speed signal transmission	High-power electrical transmission	High-density signal/power interconnection
Key Challenge	Impedance matching, signal integrity	Thermal management, contact resistance	Micro-precision manufacturing, space efficiency
Frequency / Current	100 MHz ~ 110 GHz	10A ~ 1000A+	0.3A~5A per terminal (signal)
Typical Pitch	N/A (coaxial structure)	2.54mm ~ 15mm+	0.2mm ~ 1.0mm
Core Materials	Brass + Au/Ag plating, PTFE dielectric	Copper alloy + Ag plating, LCP/PBT+GF	BeCu/CuNiSi alloy, LCP/PPS ultra-thin plastic
Key Parameters	VSWR, Insertion Loss, Characteristic Impedance Z₀	Contact Resistance, Temp. Rise, Current capacity, IP rating	Pitch, Stacking Height,Differential Impedance, Crosstalk
Test Equipment	Network Analyzer, TDR	Micro-ohmmeter, Temp. Rise Test	Microscope, X-Ray, TDR
Typical Applications	5G base stations, radar, satellites,test equipment, Wi-Fi/Bluetooth	Electric vehicles, energy storage, industrial power, charging stations	Smartphones, servers, medical electronics, aerospace
Major Standards	MIL-STD-348 IEC 61169	UL 1977, IEC 61984 GB/T, SAE J1742	EIA/JEDEC MIL-DTL-83513
Major Standards	MIL-STD-348 IEC 61169	UL 1977, IEC 61984 GB/T, SAE J1742	EIA/JEDEC MIL-DTL-83513
Cost Structure	Medium-High (precision machining+ precious metal plating)	Medium (high material cost but relatively simple structure)	High (micro-machining+ selective gold plating)
Cost Structure	Medium-High (precision machining+ precious metal plating)	Medium (high material cost but relatively simple structure)	High (micro-machining+ selective gold plating)

Design Thinking Differences