Ublox TOBY-R2 Series System Integration Manual

Also see for TOBY-R2 Series: User guide

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Ublox TOBY-R2 Series System Integration Manual Manual pdf 32 page image

TOBY-R2 series - System integration manualUBX-16010572 - R10 System description Page 32 of 1511.7 Antenna interface1.7.1 Antenna RF interfaces (ANT1 / ANT2)TOBY-R2 series modules provide two RF interfaces for connecting the external antennas: ANT1 represents the primary RF input/output for transmission and reception of RF signals.ANT1 pin has a nominal characteristic impedance of 50  and must be connected to the primaryTx / Rx antenna through a 50  transmission line to allow proper RF transmission and reception. ANT2 represents the secondary RF input for the reception of LTE / 3G RF signals in Down-Link Rxdiversity radio technology supported by TOBY-R2 modules as required feature for LTE Cat 1 UEs.The ANT2 pin has a nominal characteristic impedance of 50  and must be connected to thesecondary Rx antenna through a 50  transmission line to allow proper RF reception.1.7.1.1 Antenna RF interfaces requirementsTable 7, Table 8 and Table 9 summarize the requirements for the RF interfaces (ANT1 / ANT2). Seesection 2.4.1 for suggestions to properly design antennas circuits compliant with these requirements.⚠ The antenna circuits affect the RF compliance of the device integrating TOBY-R2 series moduleswith applicable required certification schemes (for more details see section 4). Compliance is metby fulfilling the requirements for the antenna RF interfaces (ANT1 / ANT2) summarized in Table 7,Table 8 and Table 9.Item Requirement RemarkImpedance 50  nominal characteristicimpedanceThe impedance of the antenna RF connection must match the 50 impedance of the ANT1 port.FrequencyRangeSee the TOBY-R2 series datasheet [1]The required frequency range of the antenna connected to ANT1 portdepends on the operating bands of the used cellular module and theused mobile network.Return Loss S11 < -10 dB (VSWR < 2:1)recommendedS11 < -6 dB (VSWR < 3:1) acceptableThe Return loss or the S11, as the VSWR, refers to the amount ofreflected power, measuring how well the antenna RF connectionmatches the 50  characteristic impedance of the ANT1 port.The impedance of the antenna termination must match as much aspossible the 50  nominal impedance of the ANT1 port over theoperating frequency range, reducing as much as possible the amountof reflected power.Efficiency > -1.5 dB ( > 70% ) recommended> -3.0 dB ( > 50% ) acceptableThe radiation efficiency is the ratio of the radiated power to the powerdelivered to antenna input: the efficiency is a measure of how well anantenna receives or transmits.The radiation efficiency of the antenna connected to the ANT1 portneeds to be enough high over the operating frequency range to complywith the Over-The-Air (OTA) radiated performance requirements, asTotal Radiated Power (TRP) and the Total Isotropic Sensitivity (TIS),specified by applicable related certification schemes.Maximum Gain According to radiation exposurelimitsThe power gain of an antenna is the radiation efficiency multiplied bythe directivity: the gain describes how much power is transmitted inthe direction of peak radiation to that of an isotropic source.The maximum gain of the antenna connected to ANT1 port must notexceed the herein stated value to comply with regulatory agenciesradiation exposure limits.For additional info see sections 4.2.2 and/or 4.3.1Input Power > 33 dBm ( > 2 W ) for TOBY-R200> 24 dBm ( > 0.25 W ) for TOBY-R202The antenna connected to the ANT1 port must support with adequatemargin the maximum power transmitted by the modulesTable 7: Summary of primary Tx/Rx antenna RF interface (ANT1) requirements