User Guide

ME3630

Hardware Development Guide

Keep a proper distance between main and diversity antenna to improve the receiving sensitivity.

3.3. REFERENCE PCB LAYOUT OF ANTENNA

Please follow the following criterion in the process of antenna line PCB layout design:

Make sure that the transmission line’s characteristic impedance is 50ohm;

Keep line on the PCB as short as possible, since the antenna line loss shall be less than 0.3 dB;

Line geometry should have uniform characteristics, constant cross section, avoid meanders and abrupt curves;

It is wise to surround the PCB transmission line with ground, avoid having other signal tracks facing directly the antenna line

track.

Keep at least one layer of the PCB used only for the ground plane; and use this layer as reference ground plane for the

transmission line;

 The ground surrounding the antenna line on PCB has to be strictly connected to the main Ground Plane by means of via

holes (once per 2mm at least), placed close to the ground edges facing line track;

 Place EMI noisy devices as far as possible from modules antenna line;

 Keep the antenna line far away from the module power supply lines;

3.4. SUGGESTIONS FOR EMC & ESD DESIGN

3.4.1. EMC DESIGN REQUIREMENTS

During the design of the whole device, the user needs to fully consider the EMC problem caused by the signal integrity and

power integrity.

During the product design, it is better to separate the module from the mainboard PCB, instead of installing the module on the

ground of the mainboard. If they cannot be separated, the module should be far from modules and components that might generate

EMI, such as chip and memory, power interface, and data cable interface.

Because the mainboard of PAD, CPE, and Internet laptops does not have a shielding cover, as that of mobile terminals, to shield

most circuits to avoid overflow of electromagnetic interference, you can spray conductive paint on the surface on non-antenna areas

within the structural components above and below the mainboard, and the conductive paint should be connected to the ground on

the mainboard by several points to shield electromagnetic interference.

Besides, data cables of the LCD and the camera might introduce interference signals, which affect the receiving performance of

the antenna. Thus, it is necessary to wrap conductive cloth around the two data cables and connected them to the ground.

RF cables of the antenna should be far from modules and components that might generate EMI, such as chip and memory,

power interface, and data cable interface. The wiring of RF cables should be close to the ground of the mainboard.

During the layout and wiring of peripheral circuits, for the wiring of power and signal cables, keep a distance of 2 times of the

line width, so as to effectively reduce the coupling between signals and keep a clean reflux path for the signal.

During the design of peripheral power circuits, the de-coupled capacitor should be placed closed to the module power PIN, the

high-frequency high-speed circuit and the sensitive circuit should be placed far away from the border of PCB. They should better be

separated during layout, so as to reduce the interference between them and protect the sensitive signal.

For the circuit or device on the side of system board that might interfere with the module, it should be shielded during design.

3.4.2. ESD DESIGN REQUIREMENTS

Module is embedded on the side of system board, so the user needs to make the ESD protection during design. For the key

input/output signal interface, such as the (U)SIM card signal interface, the ESD device should be placed closely for protection.

Besides, on the side of main board, the user should reasonably design the structure and PCB layout, guarantee that the metallic

shielding shell is fully grounded, so as to leave a smooth discharge channel for ESD.