1. Mobile System Antennas u Part of system u Propagation effects u Environment u Platform u Manufacturing u Performance u cannot be isolated u diversity control u pattern to match u body effects / hazards u exploit new technology u reliable / user friendly DESIGN CONSIDERATIONS

2. ANTENNA SYSTEM PROPAGATIONENVIRONMENT

3. Mobiles Pagers weight Volume 10g 100g 700g 87 97 100cc1000cc Size and Weight Trends in Mobiles & Pagers 87 97

4. Mobiles Pagers Volume 2002 97 100cc1000cc Size now becoming limited by practicality of use rather than technology

5. Antenna Gain u Achieved by focussing (Directivity) u Inversely proportional to beamwidth u Expressed relative to “isotropic” source or “dipole” source u Proportional to “effective” aperture u Inversely proportional to wavelength squared u Gain = Efficiency x Directivity =

6. Polarisation u Defined by the direction of the E-Field u For a dipole is in line with the dipole axis u Can be linear (V/H), circular (RH / LH) or elliptic (RH / LH) u Dual polarisation can be used for diversity

7. Radiation Hazards? u Basic safe power density level ˜ 50W/m 2 u NRPB recommended maximum Specific Absorption Rate (SAR) = 0.1W in any 10g of head tissue u ANSI controlled exposure limit = 0.4mW/g (averaged over the body); 8mW/g peak (over 1g); averaging time 6 min.

8. Antenna gain is given by: A e is the effective aperture A e < physical aperture (eg dish) A e > physical aperture (eg dipole)

9. Gain is achieved by focussing. The focussing is described by beamwidth & directivity. Directivity increases as beamwidth reduces. The beam gets narrower as the antenna is made larger. Beamwidth is inversely proportional to antenna dimension

10. Directivity is inversely proportional to beamwidth: Gain is: efficiency x directivity

11. Radiation pattern for a rectangular aperture (3 by 2 ) in dB magnitude polar form:

12. Radiation pattern for a rectangular aperture (3 by 2 ) in linear magnitude Cartesian form:

13. Radiation pattern for a 3 by 2 planar array with beam steering, in linear magnitude polar form:

14. Radiation pattern for a 3 by 2 planar array with beam steering, in linear magnitude Cartesian form: