The **ALR-322-R/Q** is a high-performance **RFID Antenna** manufactured by Alien Technology. It is specifically designed for use with UHF (Ultra High Frequency) RFID readers to provide circular polarization, which is essential for reading tags in various orientations. --- ### 1. Key Technical Specifications The "R/Q" designation usually refers to the specific connector types or regional frequency tuning (often Right-Hand Circularly Polarized). | Feature | Specification | | :--- | :--- | | **Frequency Range** | 865 - 928 MHz (Global UHF) | | **Gain** | 8.5 dBic (Circular) | | **Polarization** | Circular (RHCP) | | **Connector Type** | Type N Female | | **Input Impedance** | 50 Ohms | | **VSWR** | ≤ 1.3:1 | | **IP Rating** | IP67 (Dust and Water resistant) | --- ### 2. Electronic Component Breakdown Unlike active electronic devices (like the reader itself), the ALR-322 is a **passive component**. Its internal structure focuses on electromagnetic wave propagation. #### A. Microstrip Patch Array Inside the housing is a series of conductive "patches" etched onto a dielectric substrate. These patches are engineered to oscillate at the UHF frequency (902-928 MHz for US or 865-868 MHz for EU). #### B. Phasing Harness (Circular Polarization) To achieve **Circular Polarization**, the electronic feed network uses a phasing harness. This splits the signal into two components with a 90-degree phase shift. * **Benefit:** This allows the antenna to read RFID tags regardless of whether the tag is held horizontally or vertically. #### C. Impedance Matching Circuit The antenna includes an internal matching network to ensure the input impedance remains at **50 Ohms**. This minimizes "Return Loss," ensuring that the power sent from the RFID reader is radiated outward rather than reflected back into the reader's circuitry (which could cause overheating). --- ### 3. Physical & Environmental Construction The internal electronics are protected by a ruggedized shell to ensure performance in industrial environments. * **Radome Material:** High-strength ASA plastic (UV resistant). * **Backplate:** Heavy-duty aluminum, which acts as a ground plane to direct the signal forward and prevent back-radiation. * **Sealing:** Gasket-sealed to meet **IP67** standards, making it suitable for outdoor use or wash-down environments. --- ### 4. Typical Connection Diagram ```text [RFID Reader] <---- (LMR-400 Coaxial Cable) ----> [ALR-322-R/Q Antenna] | | (Generates Signal) (Radiates EM Waves) ```