Application Note

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: mlcc@vishay.com
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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
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For technical questions, contact: mlcc@vishay.com
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: mlcc@vishay.com
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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”.
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40
For technical questions, contact: mlcc@vishay.com
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: mlcc@vishay.com
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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: mlcc@vishay.com
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: mlcc@vishay.com
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.
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Fig. 8 - Recommended Ground Plane
For technical questions, contact: mlcc@vishay.com
Document Number: 45189
Revision: 08-Jul-10