VISHAY VITRAMON Ceramic Chip Antenna Application Note EVK 6040 User Guide EVALUATION KIT COMPONENTS The evaluation kit is shown in figure 1. Table 1 details the kit components. Antenna The company’s products are covered by one or more of the following: WO2008250262 (A1), US2008303720 (A1), US2008305750 (A1), WO2008154173 (A1). Other patents pending. GENERAL This document is designed to serve as a user guide for the VJ 6040 evaluation kit. It is recommended that this document be read after the following documents were viewed: • VJ 6040 datasheet Tuning circuit SMA connector Dip switch array Digital control pins DC connector • VJ 6040 application notes Fig. 1 - Evaluation Kit ITEM Antenna FUNCTIONALITY Actual ceramic chip antenna SMA connector Connect a 50 Ω RF cable to this connector, to get signals received on the antenna end Tuning circuit A digital tuning circuit used to cover the entire UHF band with 2 control pins Dip switch array Used to control the tuning circuit manually. Only pins 3 and 4 (marked D0 and D1) are in use. Pins 1 and 2 are not connected Digital control pins Used to control the tuning circuit electrically. Pins D0 and D1 are standard CMOS level digital control pins capable of supplying at least 1 mA DC connector Used to feed power to the tuning circuit. This connector is used only in the manual tuning alternative set up Document Number: 45189 Revision: 08-Jul-10 For technical questions, contact: [email protected] www.vishay.com 37 APPLICATION NOTE TABLE 1 - KIT COMPONENTS Application Note Vishay Vitramon EVK 6040 User Guide KIT SETUP There are 2 recommended alternative ways to set up the evaluation kit for testing and use. The difference between these alternatives is in the way the tuning circuit is controlled. Both alternatives are described hereafter. SET UP ALTERNATIVE 1 - MANUAL CONTROL In this alternative, the tuning circuit is controlled by the on board mechanical dip switch array. The control line voltage in this setup should be applied to the on board DC connector. A voltage of 2 V to 30 V will ensure good performance. The evaluation kit is supplied with a battery house designed to provide 3 V using two AAA batteries. SET UP ALTERNATIVE 2 - ELECTRICAL CONTROL In this alternative, the tuning circuit is controlled by the 5 pin digital connector. In order to function properly in this alternative and avoid short circuit, the following rules need to be followed: 1. Remove the batteries from the battery housing. Disconnect the DC jack from the DC connector 2. Leave all dip switches in L position (in this position, the tuning circuit control pins are in High-Z impedance, and can be controlled by the external pins). 3. Connect the GND pin on the EVK to the common ground used by the external digital control circuit. VISHAY VJ 6040 VISHAY VJ 6040 Use D0 and D1 to switch channels H Leave all switches in L position L D0 D1 D1 D0 GND 50 Ω RF cable to receiver/test equipment DC feed to tuning circuit H L D0 D1 50 Ω RF cable to receiver/test equipment D1 D0 GND To external digital control circuit AAA 1.5 V APPLICATION NOTE AAA 1.5 V Fig. 2 - Manual Control Fig. 3 - Electrical Control In set up alternative 1, the tuning circuit is driven and controlled by dip switches D0 and D1. The other two switches in the array are not connected. Maximum current consumed by the tuning circuit is less than 2 mA when operating at 3 V. The 3 pin digital connector is expected to be connected to an external control circuit. The digital control signals D0 and D1 are standard CMOS level signals. Note • Signal integrity is detailed in table 2 A 50 Ω RF cable, connected to the SMA connector, can be used to guide the received signals from the antenna to the desired applicable receiver/test equipment. Note • See table 3 for details regarding channel selection www.vishay.com 38 For technical questions, contact: [email protected] Document Number: 45189 Revision: 08-Jul-10 Application Note Vishay Vitramon EVK 6040 User Guide CONTROL SIGNAL INTEGRITY Table 2 describes the desired control signal properties: TABLE 2 - SIGNAL INTEGRITY FOR ELECTRICAL CONTROL ALTERNATIVE PARAMETER SYMBOL MIN. TYP. MAX. UNITS COMMENTS Equivalent DC Circuit Vih Logical LOW - 0.3 0 0.2 V 1 kΩ Vil Vih 2 3 5 V Source current Isource 0 0.01 0.05 mA Vin = 5 V This is diode reverse leakage current Sink current Isink 4 4.2 5 mA Vin = - 0.5 V 1 kΩ Vih Logical HIGH OPERATING THE KIT To properly operate the kit, the antenna needs to be tuned to the required band. The kit is offering coverage of the entire UHF band, by dividing it into 4 sub-bands. Selecting the correct band is critical for antenna performance. For technical questions, contact: [email protected] www.vishay.com 39 APPLICATION NOTE Document Number: 45189 Revision: 08-Jul-10 Application Note Vishay Vitramon EVK 6040 User Guide Table 3 describes channel selection for both manual and electrical set up alternatives and typical... TABLE 3 - TUNING CIRCUIT BANDS CHANNEL D1 D2 BAND (MHz) S11 (dB) 460 5 560 660 760 860 760 860 760 860 760 860 0 -5 1 H L 470 to 540 - 10 - 15 - 20 - 25 460 5 f (MHz) 560 660 0 -5 2 L L 540 to 620 - 10 - 15 - 20 - 25 460 5 f (MHz) 560 660 0 -5 3 H H 620 to 750 - 10 - 15 - 20 APPLICATION NOTE - 25 460 5 f (MHz) 560 660 0 -5 4 L H 750 to 860 - 10 - 15 - 20 - 25 f (MHz) Comment: The EVK tuning circuit is optimized to cover the band of 474 MHz to 800 MHz. There is an alternative tuning circuit available, to cover the band of 474 MHz to 860 MHz. For more information see “VJ 3505 application notes - tuning circuit”. www.vishay.com 40 For technical questions, contact: [email protected] Document Number: 45189 Revision: 08-Jul-10 Application Note Vishay Vitramon EVK 6040 User Guide VJ 3505 EVALUATION KIT ANTENNA PERFORMANCE MEASURED PEAK GAIN AND EFFICIENCY The Antenna radiation characteristics are influenced by several factors including ground plane dimensions and impedance matching network. The antenna parameters presented hereafter were measured using to the configuration suggested by the VJ 6040 evaluation board. Figure 4 shows radiation patterns of the EVK 6040 in various frequencies across the UHF band: Performance - Radiation Patterns (VJ 6040) 0 - 10 - 20 - 30 - 40 - 50 500 MHz 600 MHz 700 MHz 800 MHz Fig. 4 - Peak Gain vs. Frequency Applications that do not require full coverage of the UHF band can enjoy additional efficiency by removing the tuning circuit. In this case the antenna can be fixed to any 150 MHz band within the UHF range. Figure 5 shows simulated peak gain and radiation efficiency of the VJ 6040 antenna over frequency throughout the UHF band, compared with the MBRAI requirements: 0 Simulated Measured -4 -6 Standard -8 - 10 - 12 450 500 550 600 650 700 750 Frequency (MHz) 800 850 900 Fig. 5 - Peak Gain vs. Frequency Document Number: 45189 Revision: 08-Jul-10 For technical questions, contact: [email protected] www.vishay.com 41 APPLICATION NOTE Peak Gain (dBi) -2 Application Note Vishay Vitramon EVK 6040 User Guide SCHEMATIC DRAWING Figure 6 below shows the schematic drawing of the evaluation kit. See tuning circuit application note for details regarding recommended BOM. VJ 6040 C6 L1 L3 R1 Digital Input 1 D1 D1 C1 L4 R2 D2 L2 L5 R3 Digital Input 2 D2 C4 C5 C7 C2 Dip Switch 50 Ω RF feed VCC DC Jack D1 D2 APPLICATION NOTE Fig. 6 - EVK 3505 Schematic TABLE 4 - EVK6040 BOM LIST VALUE Antenna 120 nH PIN diode 27 nH 39 nH 3.3 pF 2.2 pF 220 pF 1 kΩ 0Ω REFERENCE VJ 3505 l3, l4, l5 D1, D2 L1 L2 C1 C5 C2, C4, C6, C7 R1, R3 R2 QUANTITY PER CIRCUIT PART NUMBER 1 VJ 3505M011SXMSRA0 3 HK1005R12J-T 2 BAR63-02V 1 IMC0402ER27NJ 1 IMC0402ER39NJ 1 VJ0402A3R3BXACW1BC 1 VJ0402A2R2BXACW1BC 4 VJ0402A221JXACW1BC 2 CRCW1KJNED 1 CRCW0R0Z0ED MANUFACTURER Vishay Taiyo Yuden Infineon Vishay Vishay Vishay Vishay Vishay Vishay Vishay Features are subject to revisions or changes without notification www.vishay.com 42 For technical questions, contact: [email protected] Document Number: 45189 Revision: 08-Jul-10 Application Note Vishay Vitramon EVK 6040 User Guide ELECTRICAL CHARACTERISTICS AND FUNCTIONAL DESCRIPTION The tuning circuit herein is effectively an inductor, connected in series with a capacitor. The total impedance generated by this circuit can be described in the following equation (excluding the capacitors C2, C3 and C4): Z = Z L + Z C + Z L = j * (ω L 1 − 1 1 2 ω = 2π f 1 ω C1 + ω L 2) By connecting PIN diodes in parallel to C1 and L2, the tuning circuit can electrically short-circuit one of the two reactants or both. Table 2 is detailing all logical states of the tuning circuit, and the electrical effect as presented in the impedance Z. For the sake of small signal analysis, when the PIN diode is in forward conductance mode, it is represented as a 2 Ω resistor. TABLE 5 - TUNING CIRCUITS' IMPEDANCES DIGITAL INPUT 1 DIGITAL INPUT 2 PIN 0 PIN 1 0 0 High Z High Z 0 1 High Z Z (W) j * ( ω L1 − 2Ω 1 ω C1 j * ( ω L1 − + ω L2 ) 1 )+ 2 ω C1 1 0 2Ω High Z j * ( ω L1 + ω L2 ) + 2 1 1 2Ω 2Ω j * ω L1 + 4 As evident from table 2, each one of the 4 possible logic states represents a different tuning circuit between the antenna and the receiver port. By applying the values shown in table 1 to L1, C1 and L2 the 4 states cover the entire UHF band. SELECTING THE RESISTIVE VALUES OF R R1 resistor is used to DC bias the PIN diodes. Selecting the value for R1 can be derived for the following equation: Vcontrol - Vd Id Let's assume that the digital control line is 1.8 V when high. To allow a current of 1 mA, R1 should be set as follows: When: R = resistive value (in Ω) for R1 Vcontrol = control voltage (in volts) as generated by the controller Vd = forward voltage (in V) generated on the PIN diode when biased R1 = 1 .8 - 0 .8 = 1 kΩ 0 . 001 Id = forward current (in A) through the PIN diode when biased Document Number: 45189 Revision: 08-Jul-10 For technical questions, contact: [email protected] www.vishay.com 43 APPLICATION NOTE R = Example: The PIN diode should be forward biased at 0.8 V to allow just over 1 mA to pass through it (see the graphs below). At 1 mA, the diode small signal impedance drops to its required value of 2 Ω. Application Note Vishay Vitramon EVK 6040 User Guide 6 100.00 f = 100 MHz RF- Forward Resistance (Ω) I F - Forward Current (mA) 5 10.00 1.00 0.10 4 3 2 1 0.01 0 0.5 18325 0.6 0.7 0.8 0.9 1.0 0.1 VF - Forward Voltage (V) 100 10 1.0 18341_1 IF - Forward Current (mA) Fig. 7 - PIN Diode Characteristics GROUND PLANE CONFIGURATION General 10.5 mm 40 mm 35 mm Additional antenna VISHAY VJ 6040 Tuning Circuit 90.5mm Receiver 77 mm 50 Ohm An important consideration in the design of this product into cell phone applications is the coexistence of the cell phone antenna with VJ 6040. The recommended ground plane configuration presented below includes recommendations regarding how to set the cellular antenna relative to the VJ 6040 to minimize losses to both antennas. 3 mm The VJ 6040 antenna is unbalanced, therefore requiring a ground plane for its operation. The ground plane dimensions significantly influence the antenna performance. The rule of thumb in unbalanced antenna ground plane design is that antenna efficiency increases with ground plane size. The evaluation board demonstrates how the antenna complies with the EMBRAI standard when set against a ground plane small enough to fit into most cellular phone designs. Applications that allow larger ground planes can enjoy higher efficiency. APPLICATION NOTE VJ 6040 evaluation board demonstrates exceptional antenna performance achieved with a 40 mm by 80 mm ground plane. Figure 4 describes a recommended reference ground plane configuration. The areas marked in green in the close proximity to the antenna should remain empty from large conducting surfaces including ground planes (outer or inner layers), batteries, connectors, buttons, or other large components. Applications that require additional antennas, such as cell phones, should position the cellular antenna at the top left hand side while maintaining maximum distance from VJ 6040. The presence of an additional antenna might cause loss of efficiency to both antennas. www.vishay.com 44 Fig. 8 - Recommended Ground Plane For technical questions, contact: [email protected] Document Number: 45189 Revision: 08-Jul-10