Why a GSM Quad Band antenna on 60 mm x 30 mm ground plane will not radiate well?

Q: I am trying to figure out if it is possible to design a reasonable quad band on a PCB that has a total overall size (ground plane plus antenna) of about 60x30mm, using a GSM module. Have you ever tried something around this size?

A: Some chapters out of my IoT M2M book:
7    Simulation of an embedded GSM PCB track antenna    26
7.1    Definition of the antenna simulation project    26
7.2    Description of the inverted F antenna    26
7.3    3D model of the simulation    27
7.4    Optimization – determination of antenna shape    28
7.5    Typical requirements of a quad band GSM antenna    28
7.6    Optimization of the quad band antenna GSM antenna shape    31
7.7    Directional characteristics of the antenna for two GSM frequencies    31
7.8    Influence on the antenna characteristics of the housing    34
7.9    Influence of the ground plane on the antenna characteristics    35

Chapter 7.9 shows you in detail what will happen on a too small ground plane. 60 mm x 30 mm is very small. Just have a look on some SMT mounted cellular antennas und you will see, that they are all on 45 mm +/-5 mm x 100 mm +/- 10 mm ground plane. The simulation in the book shows that the antenna efficiency will drop dramatically on 45 mm x 45 mm at the lower GSM band 850/900 and for the higher GSM band 1800/1900 it is still fine. This is logical, because the wavelength at GSM 1800/1900 is estimated the half of GSM 850/900.

If you still not sure which antenna to select and why, then do not hesitate to drop an email to harald.naumann (at) gsm-modem.de

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