Microwave Engineering Europe - June 2008 - (Page 29)

BLUETOOTH 29 held constant for both measurements to establish a common reference plane. A 15 dB attenuator pad was inserted in the 802.11 measurement to drive a lower signal level to the SA front end and hence get a lower noise ﬂoor reading by turning down the input attenuation on the SA. Figure 6 shows the spectrum analyzer measurements of in-band and out-of-band emissions for an off-the-shelf 802.11g card with an external antenna connector (red) and a WiMedia UWB radio operating above 6 GHz (green). Results show that 802.11 out-of-band emissions in the WiMAX, UMTS, and LTE bands exceed the protection limit by about 30 dB, while UWB emissions are 5 dB lower than the protection limit. This means that the 802.11-based high speed Bluetooth will interfere with IMT-2000 services unless they are located approximately 8 meters apart for 2.6 GHz and 16 m apart at 2.3 GHz. If they are colocated in a single device, achieving this level of isolation between radios is unrealistic. Therefore, the most practical solution in such co-located cases would be to timesynchronize transmission and reception of different radios, i.e. one must be turned Figure 6: In-band and out-of-band emissions for an off-the-shelf 802.11g card. The red slashed lines show where the card’s emissions exceed the ECC protection level. The green line shows the performance of a WiMedia UWB radio operating above 6 GHz (which is where the UWB AMP will operate). off for the other to operate. This could make receiving a WiMAX call while using a high-speed Bluetooth feature impossible to achieve. Figure 6 also shows that the UWB emission in the IMT-2000 bands is below the protection level and it doesn’t cause any interference. This means that the WiMedia UWB AMP can be used in conjunction with IMT-2000 services, even co-located in the same device. extend your connections wireless.wideband.mobile.power.zigbee.bluetooth. get the whole picture electronica wireless at the world’s leading trade fair for electronics: mobile communications, progress and innovation, leading international manufacturers, experts and decision-makers—a unique industry gathering that focuses on the most important topics, trends and technologies for the wireless future. www.electronica.de/wireless Be sure to visit the concurrent trade fair www.hybridica.de electronica 2008 wireless 23rd world’s leading trade fair New Munich Trade Fair Centre November 11–14, 2008 Microwave Engineering ● June 2008 ● www.mwee.com http://www.electronica.de/wireless http://www.electronica.de/wireless http://www.hybridica.de http://www.mwee.com

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Microwave Engineering Europe - June 2008 Contents Comment News Cover Feature Designing and Simulating a Wireless LAN Antenna 60GHz: Achieving the Ultimate Wireless Dream New Radar Developments Include HFETs to Challenge DMOS/LDMOS and a 77-GHz CMOS PA for Automotive Applications Testing Raises Concerns Over 802.11-Based High-Speed Bluetooth IP2 & IP3 Design Considerations with Direct Conversion I/Q Demodulator Receiver Products Calendar

Microwave Engineering Europe - June 2008

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