ANT-433-USP Data Sheet by Product Description 12.70 mm The Splatch uses a grounded-line technique (0.5 ) to achieve outstanding performance from a tiny surface-mount element. This unique antenna is designed for hand or reflow-mounting directly to a 9.14 mm (0.36 ) products circuit board. Its low cost makes it ideal for volume applications. Unlike many compact 2.62 mm antennas, the Splatch exhibits good proximity (0.103 ) performance, making it an appropriate choice for 5.1 mm 1.27 mm handheld applications such as remote controls, (0.20 ) (0.05 ) pagers and alert devices. Features Recommended Footprint Very low cost 5.1 mm Ultra-compact package (0.20 ) Direct PCB attachment 2.54 mm Ideal for concealed / internal mounting (0.10 ) Perfect for compact portable devices Suitable for hand- or reflow-assembly 2.03 mm Resistant to proximity effects (0.08 ) Recommended Mounting Electrical Specifications 40.37 mm (1.59) Center Frequency: 433MHz 7.11 mm Recom. Freq. Range: 429.5 436.5MHz (0.28) Bandwidth: 7MHz No ground plane or traces 10.54 mm under the antenna Wavelength: -wave (0.42) PCB pads for the Splatch VSWR: 2.0 typical at center Vias to ground plane Peak Gain: 9.8dBi Ground plane on bottom Impedance: 50-ohms layer for counterpoise 50-ohm microstrip line Connection: Surface-mount (0.21 minimum) Oper. Temp. Range: 40C to +130C Electrical specifications and plots measured on 3.88 cm x 8.00 91.82 mm 79.88 mm (3.62) cm (1.53 x 3.15) reference ground plane. (3.15) Ordering Information ANT-433-USP (supplied in tubes of 63 pieces) ANT-433-USP-T (Tape and reel of 1,000 pieces) 7.62 mm 7.62 mm (0.03) 38.86 mm (0.03) (1.53) Please see AN-00502 for more details on PCB layout. 1 Revised 1/3/2017Counterpoise Quarter-wave or monopole antennas require an associated ground plane counterpoise for proper operation. The size and location of the ground plane relative to the antenna will affect the overall performance of the antenna in the final design. When used in conjunction with a ground plane smaller than that used to tune the antenna, the center frequency typically will shift higher in frequency and the bandwidth will decrease. The proximity of other circuit elements and packaging near the antenna will also affect the final performance. For further discussion and guidance on the importance of the ground plane counterpoise, please refer to Linx Application Note AN-00501: Understanding Antenna Specifications and Operation. VSWR Graph VSWR 1.65 Reflected Power 25% 3:1 11% 2:1 0% 1:1 383MHz 433MHz 483MHz What is VSWR The Voltage Standing Wave Ratio (VSWR) is a measurement of how well an antenna is matched to a source impedance, typically 50-ohms. It is calculated by measuring the voltage wave that is headed toward the load versus the voltage wave that is reflected back from the load. A perfect match has a VSWR of 1:1. The higher the first number, the worse the match, and the more inefficient the system. Since a perfect match cannot ever be obtained, some benchmark for performance needs to be set. In the case of antenna VSWR, this is usually 2:1. At this point, 88.9% of the energy sent to the antenna by the transmitter is radiated into free space and 11.1% is either reflected back into the source or lost as heat on the structure of the antenna. In the other direction, 88.9% of the energy recovered by the antenna is transferred into the receiver. As a side note, since the :1 is always implied, many data sheets will remove it and just display the first number. How to Read a VSWR Graph VSWR is usually displayed graphically versus frequency. The lowest point on the graph is the antennas operational center frequency. In most cases, this is different than the designed center frequency due to fabrication tolerances. The VSWR at that point denotes how close to 50-ohms the antenna gets. Linx specifies the recommended bandwidth as the range where the typical antenna VSWR is less than 2:1. 2 ANT-433-USP Data Sheet by