The **KWMS-2D-R/K** is a high-performance **Dual-Axis K-Band Microwave Sensor** commonly used in traffic monitoring, speed measurement, and security applications. It utilizes the Doppler effect to detect moving objects and can provide both speed and direction data. --- ### 1. Key Electronic Specifications The sensor operates within the K-Band frequency range, which allows for high precision and small antenna sizes. | Parameter | Specification | | :--- | :--- | | **Frequency Range** | 24.125 GHz (K-Band) | | **Operating Voltage** | 5V DC ± 5% | | **Current Consumption** | ~40mA to 60mA | | **Output Interface** | Dual Channel (I/Q) Analog / Digital Pulse | | **Detection Range** | Up to 15-20 meters (depending on object size) | | **Operating Temperature**| -20°C to +60°C | --- ### 2. Core Electronic Components The internal circuitry of the KWMS-2D-R/K is divided into several functional blocks: #### A. Microwave Transceiver (MMIC) The heart of the device is a **Monolithic Microwave Integrated Circuit (MMIC)**. It generates the 24GHz signal and transmits it via a patch antenna. When the signal reflects off a moving object, the MMIC receives the shifted frequency. #### B. Dual-Channel (I/Q) Mixer The "2D" in the model name refers to the **In-phase (I)** and **Quadrature (Q)** outputs. - By comparing the phase difference between these two signals, the electronics can determine if an object is **approaching** or **receding**. - Single-channel sensors can only detect speed, whereas this I/Q configuration allows for direction sensing. #### C. Signal Conditioning (Op-Amps) The raw Doppler signal is extremely weak (microvolts). The board contains high-gain operational amplifiers to: 1. Filter out low-frequency noise (like 50/60Hz power line hum). 2. Amplify the signal to a level readable by a Microcontroller (MCU). #### D. Patch Antenna Array Instead of a wire antenna, it uses a copper **Patch Antenna** etched directly onto the PCB. This design provides a specific "beamwidth" (usually around 80° horizontal and 32° vertical) to focus the energy in a specific direction. --- ### 3. Connection Pinout (Standard R/K Series) The sensor typically features a 4-pin or 5-pin header: 1. **VCC:** Power supply (5V). 2. **GND:** Ground. 3. **I-Output:** In-phase Doppler signal. 4. **Q-Output:** Quadrature Doppler signal. 5. *(Optional)* **IF:** Intermediate Frequency output for raw processing. --- ### 4. Comparison: R vs. K Variants While the base technology is the same, the suffix usually denotes the mounting or gain sensitivity: * **KWMS-2D-R:** Often refers to a "Round" or specific radiation pattern optimized for wide-area motion detection. * **KWMS-2D-K:** Often refers to a "Keyed" or narrow-beam version optimized for specific lane detection in traffic.