Obstructed Rf Feed Pad Or Missing Matching Circuit; Broken Or Missing Bottom Antenna Clip Or Matching Circuit - Nokia 3155 Antenna Description And Troubleshooting

3155/3155i (RM-41), 3152 (RM-61)
Antenna Description and Troubleshooting

Obstructed RF Feed Pad or Missing Matching Circuit

If any portion of the upper clip is obstructed, removed, or covered, the antenna
connector will not make contact with the PWB and the antenna performance will
degrade. If the antenna connector does not touch clip, the antenna gain will degrade by
more than 25 dB.
Switch connector
Figure 6: PWB layout of the RF feed pad and the matching circuit
The matching circuit is right next to the upper clip. The matching circuit consists of a
shunt inductor of 12nH, a series cap of 2.2pF, and a series inductor of 3.9nH. If the
matching circuit is not installed properly or any of the components are missing, the
extended antenna gain will be degraded by about 25dB and the retracted antenna gain
will degrade by about 15dB.
• If corrosion is present or the pad is missing, replace the PWB and the mobile
terminal.

Broken or Missing Bottom Antenna Clip or Matching Circuit

If the bottom antenna clip does not contact the whip stopper when the whip is fully
retracted, the antenna gain will degrade by about 4-5dB at Cell band and 3-10dB at PCS
band when the whip is retracted.
The bottom matching circuit is right next to the bottom antenna clip and consists of a
series cap of 2.7pF. If the bottom matching circuit is not installed properly or the
component is missing, then the retracted antenna gain will degrade by about 15dB.
Page 6
©2005 Nokia Corporation
Matching circuit
Company Confidential
Upper clip
ISSUE 1 07/2005