Andrey Gleener Andrey Gleener R&D Services Ltd. IEEE Joint Communications Chapter - Vancouver Ideas for Embedded Antenna Design For Small-Size and Hand-Held Devices

Apple iPhone Antenna

Antenna close to on-board components antenna developer has to extend design thought onto the whole mechanical structure surrounding the Antenna

The Usual Antenna Properties: Frequency Bandwidth Radiation pattern Gain Efficiency Polarization Technological Details: Materials Feed Mounting Issues specific to Embedded Antenna: Interaction with Surrounding Circuitry Effects of Antenna Housing Interaction with Human Body

Types of structures used as embedded antennas Dipole Monopole Helix Loop Slot Inverted F Patch

Currents localized on Antenna Structure Currents forced on Ground Plane Include Ground Plane to get larger effective aperture Avoid Ground Plane if it is excessively lossy

Simple Embedded Antenna Nordic Semiconductor evaluation board

Pattern as function of total length L < 1/4 λ E L = 1/2λ ~ L = 1λ ~~

~3/8 λ ~1/4 λ E E Polarization is Important

PIFA Planar Inverted F Antenna

PIFA from Monopole Monopole Inverted L Inverted F PIFA

PIFA from Slot Antenna Slot Half-Slot PIFA

Advantages of PIFA can be matched directly to 50 Ohm high efficiency in compact form factor reduced coupling to surrounding environment low Specific Absorption Rate can be made resonant in desired multiple frequency bands!

Dual Band PIFA Slot

Return Loss of Dual Band PIFA Antenna 5%6%

Return Loss of modern multi band cellular Antenna 19%21%

Mobile Phone Antenna Patterns Patterns are not omnidirectional Patterns are not optimal horizontally Polarization is not entirely vertical Proximity of User’s Hand and Head further changes the pattern

Trends in Embedded Antenna development: Multi-Antenna systems Antennas with reconfigurable geometry Integration of multiple dissimilar Antennas in one enclosure Use of Metamaterials in Antenna design

Antenna and Circuit on the same board

Inside Linksys Wi-Fi Card. Two Inverted-F Antennas arranged in diversity scheme. PCB Material around the antennas removed.

Ericsson T 200 Antenna

Heat Staking the Antenna Antenna Matched Antenna Not Matched

Antenna needs to be mounted specifically and precisely Antenna assembly must be highly repeatable from one assembly to another Antenna can not be loose or change position inside the package Any materials touching Antenna absorb energy Always verify that your Antenna is still matched when in production.