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G
GU.1
Visitor II
January 4, 2021
Solved

How to increase the range of CR95HF receiver on a custom PCB?

  • January 4, 2021
  • 11 replies
  • 4846 views

Hi,

I am using the following configuration.

protocol :- ISO/IEC 14443 Type A tags

TimerW value :- 0x58

Modulation Index and Receiver Gain :- 0xD0

Reader Antenna Dimensions

L=28 mm

W =28 mm

No of turns=3 turns

Find attached diagram for designator reference

C11=180pF

C12=180pF

C2=180pF

I am also using an Low pass EMI filter

L01=L02="Part number=742792042"

C01=C02=180pf

I have tried fine tuning with various capacitor combinations.

I got slightly better range of 1.3 cm when replacing C11 and C12 with 1nF capacitor.

otherwise the range is around 0.9 cm.

For Tag i am using Keyfobs tokken type tag.

Please help me understand how to obtain greater range?

Is it by changing the modulation and gain configuration?/tag used?/capacitance values? or should i redesign the antenna.?

I designed a small antenna as per edesign suite to fit CR95hF and antenna in my 30mm x 30mm PCB such that the circuits and components are in the centre of the PCB while Antenna is on the outer circling the circuit.

Kindly help me out.

Regards

Gokulan

    This topic has been closed for replies.
    Best answer by Henry Crane

    Hi Gokula,

    thanks for sharing your new designs.

    Keeping copper ground plane as shield around components is generally recommended, particularly arounbf cristal oscillator and tuning circuit. Don't know you design rules like clearance around tracks, but it is possible without living too much dead copper, you may try to restore a bit grounf plan on design with components out of the antenna. you may start ground plan on a line B1-R1 (to leave 2mm minimum between groung plan and antenna, up to the PCB border close to the crystal.

    For designs with components inside the antenna, you may just put some ground plan to shield the crystal oscillator and CR95HF.

    see pictures below, ground plan suggestion in yellow.

    best regards,

    Henry Crane

    0693W000007C9RXQA0.jpg0693W000007C9TdQAK.jpg

    11 replies

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    G
    GU.1Author
    Visitor II
    January 22, 2021

    Dear Henry Crane,

    Thanks a lot for your review.

    I will update the changes you suggested in my design and get these PCB's fabricated.

    I will share the results after testing.

    Thanks and Regards

    Gokulan

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