ATSAM4S-WPIR-RD Atmel, ATSAM4S-WPIR-RD Datasheet - Page 23

• Manufacturer Part Number: ATSAM4S-WPIR-RD
• Description: Development Boards & Kits - ARM SAM4S16 W.PIR CAMERA REF. DESIGN
• Manufacturer: Atmel

Specifications of ATSAM4S-WPIR-RD

• Rohs: yes
• Product: Reference Designs
• Tool Is For Evaluation Of: ATSAM3S4BA
• Core: ARM Cortex M3
• Interface Type: JTAG, USB
• Operating Supply Voltage: 5 V
• Data Bus Width: 32 bit
• For Use With: RF231USB-RD

5.3.4
5.4
For that reason, any unused surface should be filled with a copper plane and connected to the other ground side using
sufficient through holes. Larger copper areas should also be connected to the other side layer with a grid of vias. This
way, for an external electromagnetic field, the board will behave like a coherent piece of metal.
When a trace is cutting the plane on one side, the design should contain vias along this trace to bridge the interrupted
ground on other layers. Place vias especially close to corners and necks to connect lose polygon ends.
Feed line
Most RF parts are matched to 50Ω impedance. To connect RF parts properly together it is necessary to use a matched
RF transmission line, like microstrip or Grounded Coplanar Waveguide (GCPW). Because of the layer construction of
the RF231USB PCB and its thickness of 1.0mm, a GCPW is favorable because it requires only a small width compared
to a microstrip line.
The calculation of a GCPW refers to top and midlayer 1. The dielectric has a thickness of 380µm and a permittivity of
ε
found in [4].
The calculated and designed GCPW according to
Figure 5-6. Board layout – GCPW properties.
The thickness of top layer copper was simplified assumed with zero.
PCB details 4 and 5 – ceramic antenna with matching network
To evaluate the antenna setup a fully assembled board was used to determine the key design parameters for the
antenna configuration. Because the antenna has to operate in an environment different from that of the manufacturer’s
evaluation board, the correct frequency tuning has to be verified. The antenna tuning was realized by using a matching
circuit described in the following sections.
The used ceramic antenna (2450AT43B100 by Johanson Technology) is optimized for PCB edge mounting. There are
ground planes on two sides of the antenna, intersected with vias. The space between antenna and ground plane has no
copper. The placement as shown in
The matching of the chip ceramic antenna is done by inductors L2 and L3 placed near the antenna feed pad
and
antenna feed point impedance to 50Ω to establish a proper RF performance.
r
= 4.4 at 2400MHz. The calculation rules for designing a GCPW are very complex. A widespread explanation can be
Figure
5-8). The capacitor C41 is not assembled. The matching network in this case has the task to match the
0.2mm
Z
0
= 49.8Ω ≈ 50Ω
0.6mm
ε
r
= 4.4
0.2mm
Atmel AVR2030: ATRF231USB – Hardware User Manual [APPLICATION NOTE]
Figure 5-8
occurs according to manufacturer’s datasheet [5].
380μm
[4]
has the following properties:
42018A−AVR−08/2012
(Figure 5-7
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