GROUND GROUND GROUND GROUND GROUND ANT. FEED DATA GUIDE “SPLATCH” PLANAR ANTENNAS INTRODUCTION 0.062" The “Splatch” is a breakthrough in compact antenna 433-SP technology. It combines excellent performance and 1 GROUNDED LINE PLANAR ANTENNA cost-effectiveness into an antenna package that can be integrated, even by designers lacking RF test equipment. Despite its simplicity and ease of use the “Splatch” should 1.102" not be thought of as “just any other part”. Its correct function is critical to the performance of your overall device. Dropping the “Splatch” in the center of your board like any 433-SP popcorn IC will likely yield dismal results. It is critical to follow the guidelines below in order to obtain proper GROUNDED LINE PLANAR ANTENNA function. 1 1 0.200" 0.540" FEATURES: Physical Dimensions ■ Low Cost ■ Eliminates unsightly external antennas ■ Easily concealed 418-SP ■ Direct PCB mounting GROUNDED LINE PLANAR ANTENNA 1 ■ Reflow compatible ■ Stable grounded-line element ■ Excellent proximity performance Electrical Connections ■ 10MHz approximate useable bandwidth APPLICATIONS INCLUDE: ■ Remote control ■ Keyless entry ■ Garage / Gate openers ORDERING INFORMATION ■ Lighting control PART # DESCRIPTION ■ Medical monitoring ANT-***-SP Splatch Planar Antenna ■ Remote data transfer ***= 315, 418, 433, 868, 916 Custom frequencies available with NRE. ■ Fire / Security systems Splatch antennas are supplied in tube ■ RFID packaging - 20 pcs. per tube. Tape and reel available at extra cost on request. ■ Pagers Revised 08/13/04 418 ATTACHMENT FEED CONSIDERATIONS The antenna pads are designed to support both hand and automated Like most reduced-size antennas the “Splatch” has a fairly high Q and thus placement. Castellations have been provided to ease solder introduction exhibits narrow bandwidth characteristics. The single most critical element in during hand assembly. The parts are also fully compatible with the reflow insuring the optimum function of the “Splatch” is to minimize the length of the process for automated assembly. feed trace (Transmission Line) to the “Splatch” itself. The feed trace should be less than .25" and in all cases microstripped. The term “Microstrip” refers to a trace passed over groundplane of a width appropriate to create a 50-ohm transmission line between the module and the antenna. Since the antenna APPLICATION CONSIDERATIONS does not present a true and stable 50-ohm match, the feed trace tends to When implemented correctly the “Splatch” will yield outstanding and repeat- lower the antenna’s resonant frequency. Given the antenna’s narrow able results. However, the “Splatch” was designed with very specific feed and bandwidth, it can easily be detuned by the length of the feed trace; thus, the mounting requirements. Failure by the designer to respect these require- trace should be kept as short as possible. Additional microstrip details are ments will result in unsatisfactory performance. available in the reference section of this guide * The antenna is tuned for direct mounting to a product’s PCB. Mounting the antenna in any other manner will produce poor results. LAYOUT CONSIDERATIONS * The antenna should be fed with a trace <=.25". Longer runs or coax feeds Improper placement of planes, traces or components will result in antenna nulls are not recommended. or complete detuning. First, the area under the antenna on all board layers should be completely free of components, traces, or groundplane. In addition, * Nothing should be placed under or directly beside the antenna element. no components or traces should pass within .25" of the top, sides, front or back Generally, mounting the antenna at the front of a product as illustrated will of the antenna. Ideally the antenna will be mounted at the top of the board and yield the best results. given an unobstructed field of view in all directions. Components placed in the area below the back edge of the antenna will have little effect since the antenna has a null at its back edge when referenced appropriately to groundplane. Components placed to the sides or top of the antenna or items such as No displays mounted in proximity to the antenna will produce nulls and, possibly, Groundplane/Copper/Trace detuning. The antenna may be referenced to groundplanes of all different 433-SP Area - BARE PCB surface areas; however, it has been optimized for a 1.5"x 3" plane area. The .25" or Less GROUNDED LINE PLANAR ANTENNA 1 best performance and lowest VSWR will be obtained when referenced to a Microstripped plane of similar area. Vias To Feedline Groundplane The recommended pad layout is illustrated below. The top layer of the board generally has the antenna mounting pads and feed trace. The ground pads are connected to the groundplane layer through vias. Use care in the sizing and placement of the vias to prevent solder migration from the attachment pads Groundplane on during attachment. Rear of Board 0.090" Top Layer Vias To 0.100" Groundplane Bottom Layer Pads and outline shown for groundplane position reference only. Typical Remote Control Application Page 2 Page 3 SPLATCH SERIES PERFORMANCE DATA About These Measurements Splatch Under The typical performance graphs below were based on a "Splatch" antenna 0.550" Test affixed to the test jig illustrated, and measured with a HP-8753D network ana- lyzer in a 20°-25°C environment. Vias To *As of the time of this publication, full pattern characterization data was not avail- Groundplane able. Refer to the Linx website for periodic updates to this document. 8" of RG-174 Specification Frequency Units Notes .062 FR4 Cable Substrate 315 418 433.92 868 900 MHz Electrical Length 1/4λ 1/4λ 1/4λ 1/4λ 1/4λ 3.000" Center Frequency 315 418 433.92 868 916 MHz 1 Useable Bandwidth 10 10 10 20 40 MHz Characteristic Impedence 50 50 50 50 50 Ohms 1, 2 1 oz. Copper VSWR <1.7 Typ. <1.7 Typ. <1.7 Typ. <1.7 Typ. <1.7 Typ. 1 Groundplane Gain/ -10 -6 -5 -2 -1 1, 3, 4 on Rear Notes: 1. At Specified Frequency; 2. VSWR <2.0; 3. Relative to isotropic; 4. Preliminary TYPICAL SMITH CHART CH1 S 1: 51.189 Ω -5.3926 Ω 70.607 pF 11 1.500" 1 TESTING Several methods may be employed to verify the optimization of the “Splatch” in START FREQ. 250.000 MHz Marker 1 = 315 MHz your product design. They are listed below in order of preference. STOP FREQ. 500 MHz A) Utilize a network analyzer to verify resonance and VSWR. TYPICAL VSWR GRAPHS B) Use a Spectrum Analyzer and 315 MHz 418 MHz 433.92 MHz Signal Generator to sweep the anten- na and find the frequency of highest output. *NOTE* A characterized or calibrated antenna must be used on the Spec- trum Analyzer in order for meaningful results to be obtained. C) Test range results in your environment. If your product 900 MHz 868 MHz performs to your requirements, cease CH1 S11 SWR 1 / REF 1 hp all engineering efforts and sell it. MARKER 1 MARKER 2 MARKER 3 Start Frequency 800.000 MHz Stop Frequency 1100.000 MHz Marker 1 = 902 MHz 1.868 VSWR Marker 2 = 916 MHz 1.435 VSWR Marker 2 = 928 MHz 1.58 VSWR Page 5 Page 4 NOT AVAILABLE AT TIME OF PUBLICATION Power Conversion Tables For 50Ω System MISMATCH CONVERSION TABLE VSWR Insertion Power Power dBm mW dBmV mVRMS mVp mVpp Loss Transmitted Reflected (dB) (%) (%) -50 0.000 -3.0 0.7 1.0 2.0 17.391 -6.87 20.57% 79.43% -45 0.000 2.0 1.3 1.8 3.6 11.610 -5.35 29.21% 70.79% -40 0.000 7.0 2.2 3.2 6.3 8.724 -4.33 36.90% 63.10% 6.997 -3.59 43.77% 56.23% -35 0.000 12.0 4.0 5.6 11.2 5.848 -3.02 49.88% 50.12% -30 0.001 17.0 7.1 10.0 20.0 5.030 -2.57 55.33% 44.67% -25 0.003 22.0 12.6 17.8 35.6 4.419 -2.20 60.19% 39.81% 3.946 -1.90 64.52% 35.48% -20 0.0l 0 27.0 22.4 31.6 63.2 3.570 -1.65 68.38% 31.62% -15 0.032 32.0 39.8 56.2 112.5 3.010 -1.26 74.88% 25.12% -10 0.100 37.0 70.7 100.0 200.0 2.615 -0.97 80.05% 19.95% 2.323 -0.75 84.15% 15.85% -5 0.316 42.0 125.7 177.8 355.7 2.100 -0.5887.41% 12.59% 0 1.000 47.0 223.6 316.2 632.5 1.925 -0.46 90.00% 10.00% 1.433 -0.14 96.84% 3.16% 1 1.259 48.0 250.9 354.8 709.6 1.222 -0.04 99.00% 1.00% 2 1.585 49.0 281.5 398.1 796.2 1.119 -0.01 99.68% 0.32% 3 1.995 50.0 315.9 446.7 893.4 1.065 0.00 99.90% 0.10% 1.034 0.00 99.97% 0.03% 4 2.512 51.0 354.4 501.2 1002.4 1.020 0.00 99.99% 0.01% 5 3.162 52.0 397.6 562.3 1124.7 6 3.981 53.0 446.2 631.0 1261.9 MICROSTRIP DETAILS 7 5.012 54.0 500.6 707.9 1415.9 8 6.310 55.0 561.7 794.3 1588.7 9 7.943 56.0 630.2 891.3 1782.5 10 10.000 57.0 707.1 1000.0 2000.0 11 12.589 58.0 793.4 1122.0 2244.0 12 15.849 59.0 890.2 1258.9 2517.9 13 19.953 60.0 998.8 1412.5 2825.1 14 25.119 61.0 1120.7 1584.9 3169.8 5 31.623 62.0 1257.4 1778.3 3556.6 6 39.811 63.0 1410.9 1995.3 3990.5 17 50.119 64.0 1583.0 2238.7 4477.4 18 63.096 65.0 1776.2 2511.9 5023.8 19 79.433 66.0 1992.9 2818.4 5636.8 20 100.000 67.0 2236.1 3162.3 6324.6 21 125.893 68.0 2508.9 3548.1 7096.3 22 158.489 69.0 2815.0 3981.1 7962.1 23 199.526 70.0 3158.5 4466.8 8933.7 24 251.189 71.0 3543.9 5011.9 10023.7 Effective 25 316.228 72.0 3976.4 5623.4 11246.8 Dielectric Width/Height Dielectric Characteristic 26 398.107 73.0 4461.5 6309.6 12619.1 Constant (W/d) Constant Impedance 27 501.187 74.0 5005.9 7079.5 14158.9 4.8 1.8 3.59 50.0 28 630.957 75.0 5616.7 7943.3 15886.6 4 2 3.07 51.0 29 794.328 76.0 6302.1 8912.5 17825.0 2.55 3 2.12 48.0 30 1000.000 77.0 7071.1 10000.0 20000.0 Microstrip formulas (Er = Dielectric constant of PCB material) Page 7 Page 6 U.S. CORPORATE HEADQUARTERS: ANTENNA FACTOR, INC. 575 S.E. ASHLEY PLACE GRANTS PASS, OR 97526 Phone: (541) 956-0931 FAX: (541) 471-6251 http://www.antennafactor.com Disclaimer Antenna Factor is continually striving to improve the quality and function of its products; for this reason, we reserve the right to make changes without notice. The information contained in this Data Sheet is believed to be accurate as of the time of publication. Specifications are based on representative lot samples. Values may vary from lot to lot and are not guaranteed. Antenna Factor makes no guarantee, warranty, or representation regarding the suitability of any product for use in a specific application. None of these devices is intended for use in applications of a critical nature where the safety of life or property is at risk. The user assumes full liability for the use of product in such applications. Under no conditions will Antenna Factor be responsible for losses arising from the use or failure of the device in any application, other than the repair, replacement, or refund limited to the original product purchase price. Some devices described in this publication are patented. Under no circumstances shall any user be conveyed any license or right to the use or ownership of these patents. © 2004 by Antenna Factor, Inc. The stylized Antenna Factor logo, and Antenna Factor are trademarks of Linx Technologies, Inc. Printed in U.S.A. Page 8