GSM/DCS Dual Antenna Switch Module (ASM)
With continuously decreasing dimensions of modern mobile phones the compact design of all internal modules is an essential development goal. The structure considered is from a dual band phone (GSM 900 MHz + DCS 1800 MHz) which combines a diplexer for both bands and a low pass filter for each band. The device is only 4.5 mm by 3.2 mm and utilises LTCC technology.
Firstly, the diplexer functionality is investigated:
Figure 1: The ASM structure with the relevant ports for the diplexer mode.
In the diplexer port 2 represents the GSM, port 3 the DCS part. The following figures represent the return loss of both modes as well as the transmission to the common port 1. The left graphs show the simulations, the right ones the measurements. Excellent agreement between the results can be observed.
Figure 2: Return loss and transmission of the diplexer GSM part (simulation left, measurement right).
Figure 3: Return loss and transmission of the diplexer DCS part (simulation left, measurement right).
In the following section the both low pass filters for the GSM and the DCS bands are considered. The relevant ports for both modes are shown in the structure.
Figure 4: The ports for the GSM low pass filter in the ASM structure.
Figure 5: Simulation (left) and measurement for the GSM low pass filter.
Figure 6: The ports for the DCS low pass filter in the ASM structure.
Figure 7: Simulation (left) and measurement for the DCS low pass filter.
The copyright for the displayed structure is with "Korea Electronics Technology Institute (KETI), High Frequency Materials Research Center".
CST Article "GSM/DCS Dual Antenna Switch Module (ASM)"
last modified 15. Mar 2010 7:27
printed 15. Mar 2010 7:27, Article ID 127
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Article ID: 127
Last modified: 15. Mar 2010 7:27
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