Nokia Customer Care 6235/6235i/6236i (RM-60) Mobile Terminals Antenna Description and Troubleshooting Issue 1 04/2005 Company Confidential ©2005 Nokia Corporation
6235/6235i/6236i (RM-60) Antenna Description and Troubleshooting Contents Page Introduction ..................................................................................................................................................... 3 Visual Quality Requirements ....................................................................................................................... 3 Failures and Corrective Measures ..................................................................................
6235/6235i/6236i (RM-60) Antenna Description and Troubleshooting Nokia Customer Care Introduction The mobile terminal incorporates an internal antenna. This antenna arrangement is used for AMPS/CELL and PCS frequency bands. The internal antenna assembly consists of a Planar Inverted-F Antenna (PIFA) used for the cellular engine and an Inverted-F antenna (IFA) used for the GPS engine, which is placed on the side of internal antenna body.
6235/6235i/6236i (RM-60) Antenna Description and Troubleshooting An integrated hands-free (IHF) mini speaker is integrated inside the plastic. Main antenna radiator (PIFA) GPS antenna radiator (IFA) Figure 2: Internal antenna Note: The GPS antenna is only functional on models that support the GPS engine. Damaged RF Feed, Ground Pins, or IHF Speaker Pins The main antenna and the GPS antenna have pins (spring clips) that must properly touch the PWB. Positioning of these pogo pins is shown in Figure 3.
6235/6235i/6236i (RM-60) Antenna Description and Troubleshooting Nokia Customer Care • If the ground pin of the GPS antenna does not touch the PWB, the GPS antenna gain may degrade by more than 5 dB. • If either the RF feed pin or ground pin are broken or bent such that either pin does not touch the PWB, then replace the internal antenna. • If either the RF pin or ground pin springs appear damaged, then replace the internal antenna.
235/6235i/6236i (RM-60) Antenna Description and Troubleshooting Obstructed IHF Speaker, RF Feed, and Ground Pads The antenna module connects to the PWB at specific places. These are show in Figure 5.
Nokia Customer Care 6235/6235i/6236i (RM-60) Antenna Description and Troubleshooting CDMA OR GPS RF Connector Failure CDMA and GPS use the same type of RF connector. The RF connector fails when it does not connect the RF input to the RF output. • If this happens to the CDMA RF connector, then the antenna gain will degrade by about 25 dB. • If this happens to GPS RF connector, the GPS antenna gain will degrade by about 20 dB.
6235/6235i/6236i (RM-60) Antenna Description and Troubleshooting Grounding of Display Frame The display frame is grounded to the PWB through two ground panels. The display frame grounding impacts the radiation performance of the mobile terminal. Display frame grounding through screws Display frame grounding tabs Figure 6: Display assembly ground points Check for the following problems: • If the clips are not touching the PWB, or are corroded, obstructed, then the display frame should be replaced.
6235/6235i/6236i (RM-60) Antenna Description and Troubleshooting Nokia Customer Care Calibration Factor for PCS1900 Frequency Use a call box to turn on the transmitter of the mobile terminal with a known output power and antenna performance at the maximum output power (all bits up). Measure the transmitted power on the RF connector and through a coupler at CDMA PCS channel 1175.
6235/6235i/6236i (RM-60) Antenna Description and Troubleshooting has to be measured separately for every coupler because the path losses vary depending on the setup, cables, and attenuator. Measurement Procedure for GPS Antenna 1. Place the mobile terminal in the test adapter (DA-54) with the display up. 2. Turn on the CW signal generator [with power -110 dBm + coupler, cable, and attenuator path loss at GPS band] fed to the RF coupler. 3.
