Nokia Customer Care
2505 (RM-307)
Mobile Terminal
Antenna Description and
Troubleshooting
Issue 1 04/2007 Company Confidential © 2007 Nokia Corporation
2505 (RM-307)
Antenna Description and Troubleshooting
Contents Page
Introduction............................................................................................................... 3
Visual Quality Requirements.............................................................................3
Failures and Corrective Measures........................................................................... 3
Internal Antenna................................................................................................4
Damaged RF feeding point or Pad....................................................................4
Obstruction of the RF signal path............................................................................. 5
RF Connector Failure........................................................................................5
Page 2 © 2007 Nokia Corporation Company Confidential Issue 1 04/2007
2505 (RM-307)
Nokia Customer Care Antenna Description and Troubleshooting
Introduction
The mobile terminal incorporates an internal antenna. This antenna arrangement is
used for Cellular frequency bands. The internal antenna assembly adopts
monopole Antenna structure used for the cellular engine.
Visual Quality Requirements
Following are the minimum acceptable visual quality requirements of the internal
antenna assembly:
z No visual cracks or mechanical defects.
z No oil, dirt, or particles are found on the parts.
z Radiator must be aligned with the plastic housing.
z Radiator must be flat with no warping.
z Good connection feeding pin with feeding pad.
Failures and Corrective Measures
The internal antenna is assembled into the D Cover Assembly as shown in Figure 1.
The internal antenna is a sticker type flex film mounted on the D Cover, and there is
an antenna decoration on top of it. D Cover and antenna decoration are with the
same color (shown in Figure 1 are all white). Thus, ideally the antenna is invisible
from top.
z If no internal antenna is installed, the antenna gain is degraded by more
than 20 dB.
z If the radiator looks damaged obviously, replace it with a new antenna.
Antenna decoration
Antenna zone
Figure 1: D Cover Assembly
Issue 1 04/2007 © 2007 Nokia Corporation Company Confidential Page 3
2505 (RM-307)
Antenna Description and Troubleshooting
Internal Antenna
The internal antenna receives and transmits the signal by the contact between the
feeding pad of the D Cover and the feeding pin on the PWB. Figure 2 shows the
feeding pin (pogo pin) and its corresponding feeding pad. The pogo pin must
contact fully with its corresponding pad of the D Cover. If one of the connections is
malfunction, the antenna performance could be degraded by more than 20dB.
The feeding pad
Pogo pin
Figure 2: The connection of internal antenna
Damaged RF feeding point or Pad
The pogo pin must contact fully with its corresponding pad of the D Cover..
z If one of the connections is malfunction, the antenna performance could
be degraded by more than 20dB.
z If the pogo pin lacks for elasticity, replace the PWB.
z If the pad looks damaged obviously, replace it with a new antenna.
Figure 3: The RF feeding point and Pad
Page 4 © 2007 Nokia Corporation Company Confidential Issue 1 04/2007
2505 (RM-307)
Nokia Customer Care Antenna Description and Troubleshooting
Obstruction of the RF signal path
If the RF signal path is obstructed, broken, damaged, the cellular antenna
performance degrades.
z If the obstruction, damage of signal path happens, replace the PWB.
z If one of the components at the matching circuit is missing, broken,
replace proper component according to the latest reference document.
z If the DC resistance between signal pad and the output port of RF switch
is more than 1 ohm, replace the PWB.
Output port of RF switch
Pogo pin
Matching circuit
Figure 4:PWB layout of RF feeding path
RF Connector Failure
The RF connector fails when it does not properly connect the RF input terminal to
the RF output terminal during the SMT. If this happens the antenna gain degrades
by 25 dB. Check this by testing the resistance value between the RF input and RF
output ports of the RF connector and see if the value is close to zero. If the RF input
is not connected properly to the RF output, replace the RF connector.
Note: Perform the resistance value test without a RF cable attached to the RF
connector. Because the RF connector is also a switch, the RF output is
disconnected from the RF input when a RF cable is inserted into the RF connector.
z RF input terminal – connect to duplexer.
z RF output terminal – connect to the antenna pad through antenna
matching circuit.
z RF connector terminal – connect to a RF coaxial cable.
Issue 1 04/2007 © 2007 Nokia Corporation Company Confidential Page 5
2505 (RM-307)
Antenna Description and Troubleshooting
RF input terminal RF output terminal
Figure 5: RF input / output terminal
Note:
• QSC6010 is underfilled and cannot be replaced.
• Memory IC is underfilled and cannot be replaced.
• The Shielding Cover cannot be reused after removal.
• After using the heatgun, the domesheet is recommended to be replaced.
Page 6 © 2007 Nokia Corporation Company Confidential Issue 1 04/2007
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