User's Manual

LE940B6 Hardware User Guide

1VV0301331 Rev. 1.8 - 2017-03-15

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7. Antenna(s)

Antenna connection and board layout design are the most important parts in the full product

design, and they have a strong influence on the product’s overall performance. Read carefully and

follow the requirements and guidelines for a good and proper design.

7.1. GSM/WCDMA/TD-SCDMA/LTE Antenna Requirements

The antenna for the LE940B6 device must meet the following requirements:

Table 22: Primary Antenna Requirements

Gain Gain < 3 dBi

Impedance 50 Ohm

Input power > 33 dBm(2 W) peak power in GSM

> 24 dBm average power in WCDMA & LTE

VSWR absolute max <= 10:1

VSWR recommended <= 2:1

The antenna for a specific car model must support a given set of RF bands. This set is determined

by the region variant and the specific set of bands within (either the full band set offered by Telit

or a subset per the customer choice). The antenna must have the proper bandwidth to support

the required set of bands and meet the other performance figures according to the Table 22,

along the full bandwidth. The RF bands supported in each region variant are detailed in

Section 2.5.1, RF Bands per Regional Variant.

Since there is no antenna connector on the LE940B6 module, the antenna must be connected to

the LE940B6 antenna pad (AD1) by a transmission line implemented on the PCB.

If the antenna is not directly connected to the antenna pad of the LE940B6, a PCB line is required

to connect to it or to its connector.

7.2. GSM/WCDMA/TD-SCDMA/LTE Antenna – PCB Line Guidelines

• Make sure that the transmission line’s characteristic impedance is 50 Ohm.

• Keep the line on the PCB as short as possible since the antenna line loss should be less than

around 0.3 dB.

• Line geometry should have uniform characteristics, constant cross sections, and avoid

meanders and abrupt curves.

• Any suitable geometry/structure can be used for implementing the printed transmission line

affecting the antenna.