Antenna Performance In Your Headset THE RESULTS OF HUMAN HEAD INTERACTION TESTS

Transcription

1 Antenna Performance In Your Headset THE RESULTS OF HUMAN HEAD INTERACTION TESTS Micro Reach Xtend TM (FR05-S1-N-0-110) Space Saving AN for Bluetooth and WiFi Headsets GHz Fractus Antennas specializes in enabling effective mobile communications by designing and manufacturing optimized antenna products that will make your wireless devices more competitive. Our mission is to transform our clients product development processes with innovative components that accelerate time-to-market without compromising functionality. Fractus Antennas products are protected by Fractus patents. All information contained within this document is property of Fractus Antennas and is subject to change without prior notice. Information is provided as is and without warranties. It is prohibited to copy or reproduce this information without prior approval. Fractus Antennas is an ISO 9001:2008 certified company. All our antennas are lead-free and RoHS compliant. Micro Reach Xtend TM FR05-S1-N Last updated in July FRACTUS ANTENNAS, S.L. - 1

2 TABLE OF CONTENTS 1. PRODUCT DESCRIPTION FR05-S1-N EVALUATION BOARD QUICK REFERENCE GUIDE EVALUATION BOARD ( GHz) MATCHING NETWORK VSWR AND TOTAL EFFICIENCY RADIATION PATTERNS, GAIN, AND EFFICIENCY HUMAN HEAD IMPACT SET-UP MATCHING NETWORK VSWR AND TOTAL EFFICIENCY RADIATION PATTERNS, GAIN, AND EFFICIENCY Last updated in July FRACTUS ANTENNAS, S.L. - 2

3 1. ANTENNA DESCRIPTION Headsets and other mobile devices designed to be used close to the head and body require special testing to ensure adequate performance in real use conditions. The ever increasing pressure to introduce headsets that are every time more sleek and streamlined mean engineers also need to find compact options they can rely on. We ve used our phantom head and an anechoic chamber to thoroughly test our Micro Reach Xtend Chip Antenna s performance when used touching and at various close distances to the human head. The results of our tests are presented here and will help you understand the performance you can expect from this antenna under normal use conditions for headsets, allowing you to create more reliable connectivity and add value to your headsets and other mobile devices. The Micro Reach Xtend Chip Antenna combines a miniature size with a reduced requirement for clearance area within the customer PCB for further space saving. Reduced requirements for clearance area also give designers more flexibility with design and the layout of components. With its high performance and integration flexibility, as well as its low cost, this miniature antenna has been specially designed and tested to provide Bluetooth and WiFi ( GHz) connectivity in headsets. This antenna is built on glass epoxy substrate which makes it ideal for small consumer electronics devices such as small wireless headsets and highly integrated multifunction mobile headsets. TOP 3.8 mm 4.1 mm BOTTOM 2.0 mm 1.0 mm Material: The Micro Reach Xtend TM antenna is built on glass epoxy substrate. APPLICATIONS Headsets USB Dongles Medical devices Hearing-aids Handsets Sensors (Proximity, etc.) BENEFITS Small form factor and footprint Reduced required clearance area within PCB Cost-effective Easy to integrate (pick and place) Last updated in July FRACTUS ANTENNAS, S.L. - 3

4 2. EVALUATION BOARD 2.1. QUICK REFERENCE GUIDE Technical Features Frequency Range GHz Average Efficiency 54.2 % Peak Gain 0.8 dbi VSWR < 2:1 Radiation Pattern Omnidirectional Weight (approx.) 0.02 g Temperature -40 to 85º C Impedance 50 Ω Dimensions (L x W x H) 4.1 mm x 2.0 mm x 1.0 mm Table 1 Technical Features. Measurements from the Evaluation Board (Figure 1). Please contact info@fractusantennas.com if you require additional information on antenna integration or optimization on your PCB EVALUATION BOARD ( GHz) This Evaluation Board EB_FR05-S1-N integrates a microstrip transmission line to connect the Micro Reach Xtend TM Chip Antenna with the SMA connector. The reduced dimensions of this antenna part make it particularly suitable for small devices such as headsets. The Micro Reach Xtend TM provides operation in the frequency region from 2.4 GHz to 2.5 GHz. Figure 1 EB_FR05-S1-N Evaluation Board providing operation from 2.4 GHz to 2.5 GHz. Measure mm A 35.0 B 20.0 C 40.0 D 5.2 E 20.0 F 12.5 Tolerance: ±0.2 mm Material: The Evaluation Board is built on FR4 substrate. Thickness is 1 mm. This product and/or its use are protected by at least one or more of the following patents US 7,148,850 B2; US 7,202,822 B2. Last updated in July FRACTUS ANTENNAS, S.L. - 4

5 2.3. MATCHING NETWORK The specs of a Fractus Antennas standard product are measured in an Evaluation Board, where an ideal case is created. However, when incorporating into real designs, nearby components such as LCD s, batteries, covers and connectors may affect the antenna performance. For this reason, placing pads compatible with 0402 and 0603 SMD components for a matching network as close as possible to the feeding point is highly recommended. Create this matching network in the ground plane area rather than the clearance area this will provide a degree of freedom for tuning the antenna component once the design is finished, taking into account all elements of the system (batteries, displays, covers, etc.) GHz Value Part Number 6.8 nh LQW15AN6N8G pf GJM1555C1H1R5WB01 Figure 2 Matching Network implemented in the Evaluation Board (Figure 1) VSWR AND TOTAL EFFICIENCY VSWR (Voltage Standing Wave Ratio) and Total Efficiency versus Frequency (GHz) in freespace conditions. Figure 3 VSWR and Total Efficiency (from the Evaluation Board (Figure 1)). Last updated in July FRACTUS ANTENNAS, S.L. - 5

6 2.5. RADIATION PATTERNS, GAIN, AND EFFICIENCY Measurement System Set-Up Evaluation Board in Plane XY = 90º Plane XY at 2.45 GHz = 0º Plane XZ at 2.45 GHz = 90º Plane YZ at 2.45 GHz Peak Gain 0.8 dbi Gain Average Gain across the band Gain Range across the band (min, max) 0.4 dbi 0.0 dbi 0.8 dbi Peak Efficiency 57.7 % Efficiency Average Efficiency across the band 54.4 % Efficiency Range across the band (min, max) 49.6 % 57.7 % Table 2 Antenna Gain and Total Efficiency from the Evaluation Board (Figure 1) within the GHz frequency range. Measures made in the Satimo STARGATE 32 anechoic chamber. Last updated in July FRACTUS ANTENNAS, S.L. - 6

7 3. HUMAN HEAD IMPACT In general terms, the interaction of the human body with a radiating system affects its performance, mainly through introducing efficiency decrements and detuning effects. In a headset, this interaction is pronounced due to the headset usually being directly set near to the head at a reduced distance. This section will analyze the impact of the human head (Figure 4) over the Evaluation Board (Figure 1) considering five different distances at the frequency region which covers from 2.4 GHz to 2.5 GHz. Figure 4 Phantom head used to assess the performance of the Evaluation Board (Figure 1) when operating in close proximity to the human head SET-UP The Evaluation Board (Figure 1) is placed over a phantom head which emulates the electromagnetic properties of the human head. Measurements were taken at the frequency range of GHz at different distances (Figure 5). Distance A a) Touching position b) 2mm c) 5mm d) 10mm e) 15mm Distance A Last updated in July FRACTUS ANTENNAS, S.L. - 7

8 Figure 5 Different distances between the phantom head and the Evaluation Board (which provides operation from 2.4GHz to 2.5GHz) which were used for testing MATCHING NETWORK Please note that the matching network topology has been maintained for each configuration. The component values have been re-adjusted in each case to compensate for the detuning effects introduced by the proximity of the phantom head (Figure 5) GHz Figure 6 Topology of matching network mounted for use at all of the different distances. Distance Z 1 Z 2 Touching 4.5 nh 1.0 pf 2mm 5.9 nh 1.1 pf 5mm 6.2 nh 1.2 pf 10mm 6.4 nh 1.2 pf 15mm 6.4 nh 1.3 pf Table 3 Values of the components used for each distance. Z1 Z2 Value Part Number 4.5 nh LQW15AN4N5B nh LQW15AN5N9G nh LQW15AN6N2B nh LQW15AN6N4G nh LQW15AN6N4G pf GJM1555C1H1R0WB pf GJM1555C1H1R1WB pf GJM1555C1H1R2WB pf GJM1555C1H1R2WB pf GJM1555C1H1R3WB01 Table 4 Values and part numbers of the components used for the matching networks. Last updated in July FRACTUS ANTENNAS, S.L. - 8

9 3.3. VSWR AND TOTAL EFFICIENCY VSWR (Voltage Standing Wave Ratio) and Total Efficiency versus Frequency (GHz). Figure 7 VSWR and Total Efficiency for the GHz frequency range (from the Evaluation Board (Figure 5)). Distance VSWR TOTAL EFFICIENCY (%) GHz ɳ a 1 (2.4GHz) ɳ a (2.5GHz) ɳ a (min) ɳ a (max) ɳ a (average) Free Space < 2: Touching < 1.5: mm < 1.5: mm < 1.5: mm < 2: mm < 2: Table 5 VSWR and Total Efficiency comparison considering different distances. 1 ɳ a refers to the total efficiency of the antenna system which considers both ohmic and impedance losses Last updated in July FRACTUS ANTENNAS, S.L. - 9

10 3.4. RADIATION PATTERNS, GAIN, AND EFFICIENCY Measurement System Set-Up Evaluation Board in Plane XY = 90º Plane XY at 2.45 GHz at 0mm, 2mm, 5mm, 10mm and 15mm = 0º Plane XZ at 2.45 GHz at 0mm, 2mm, 5mm, 10mm and 15mm = 90º Plane YZ at 2.45 GHz at 0mm, 2mm, 5mm, 10mm and 15mm 0mm 2mm 5mm 10mm 15mm Peak Gain -1.2 dbi 0.6 dbi 2.3 dbi 3.7 dbi 4.2 dbi Gain Efficiency Average Gain across the band Gain Range across the band (min, max) -1.6 dbi 0.0 dbi 1.8 dbi 3.1 dbi 3.7 dbi -2.5 dbi -1.2 dbi -0.9 dbi 0.6 dbi 0.7 dbi 2.3 dbi 2.4 dbi 3.7 dbi 3.0 dbi 4.2 dbi Peak Efficiency 16.0% 23.5% 34.4% 43.2% 49.9% Average Efficiency across the band Efficiency Range across the band (min, max) 15.2% 21.3% 31.6% 39.8% 46.9% 14.4% 16.0% 18.8% 23.5% 27.9% 34.4% 36.2% 43.2% 43.0% 49.9% Table 6 Antenna Gain and Total Efficiency from the Evaluation Board (Figure 1) within the GHz frequency range. Measures made in the Satimo STARGATE 32 anechoic chamber. Last updated in July FRACTUS ANTENNAS, S.L. - 10