Presentation on theme: "Welcome to gigaAnt! Your strategic 2.4 GHz antenna partner !"— Presentation transcript:
Welcome to gigaAnt! Your strategic 2.4 GHz antenna partner !
Time Table 1:30 – 2:00Greeting 2:00 – 3:50Technical Seminar Part I 3:50 – 4:10Coffee Break 4:10 – 6:00 Technical Seminar Part II
This one day course contains Antenna definition Antenna parameters Different antenna types gigaAnt standard antennas PCB issues Other factors that influence the antenna Matching and tuning Testing and verification Range
Antenna Definition A device for transmitting and receiving electromagnetic radiation Making a guided electromagnetic wave travel in free space A means for radiating or receiving radio waves, IEEE Std Antenna interaction As a result, the antenna and its surrounding needs to be regarded as a unit since they interact strongly
Electromagnetic radiation X-Ray, Light, Radio, Heat - It is all the same: Photons! c = ff = 2.45GHz = 12 cm
Influencing antenna size Material choice = permitivity FR4 4.2 in case /2 antenna, half the length Matching Adding capacitance or inductance by means of electronic components. Geometry antenna type shape (helix, spiral, meander etc.) utilise part of the application.
Frequency bands for Mobile phones MHz NMT 450 and Countries EAMPS USA GSM Europe EGSM Europe NTT Japan DCS Europe PCS USA UMTS ISM Worldwide Visible light THz ISM = Instrumentation, Scientific, Medical Bluetooth WLAN (IEEE ) HomeRF
Frequency bands for data communication WLAN MHzOn the way out GHzAvailable GHzAvailable soon GHzWill perhaps be available BT GHzAvailable GHzAvailable soon GPS 1575,42 MHzAvailable
Knowledge about the antenna parameters is needed in order for us to understand our customers and vice versa. Lobes Gain Polarisation Efficiency Frequency Band Radiation pattern Antenna parameters
Radiation pattern 3D Radiation pattern with lobes Linear plot of power pattern
Radiation intensity in a given direction,, is defined as the power radiated from an antenna per unit solid angle Radiation intensity for an isotropic source: where is the total power radiated by the source Radiation intensity
Directivity is a measure of how an antenna concentrates the radiated power in a particular direction. Directivity is the ratio of the intensity, in a given direction, to the radiation intensity that would be obtained if all the power radiated by the antenna were radiated isotropically: a unitless figure Directivity
Gain is a measure of how an antenna concentrates the radiated power in a particular direction. Gain is the ratio of the intensity, in a given direction, to the radiation intensity that would be obtained if all the power was accepted by the antenna and was radiated isotropically: a unitless figure dBi Gain
Isotropic Omnidirectional Lobes Dipole = Donut Normally measured in dB Relative unit dBi: relative ideal isotropic Isotropic radiator has 0dBi gain dBd: relative ideal dipole (1 dBd 2.14 dBi) If a gain value is given without any direction, it is the maximum gain More power in one direction at the expense of other directions Gain/Directivity
Gain: good/bad Stationary or mobile application Important to reach out in a certain direction Wall or corner position Less important inside a small room due to reflections Regulation limits ETSI EN Max 100mW eirp FCC peak power reduction when antenna gain over 6dBi
Decibel dB dBi (isotropic) dBd (dipole) dBm (miliwatt) dBw (Watt) Used to compare two figures with each other Describes better measurable steps than fractions Always unitless
Antenna efficiency (total) Good figure of merit, especially for small antennas Ratio of the power sent to the antenna to the power radiated by the antenna Unitless Ideal 1 Often given in percent Radiated efficiency is given as the ratio of the power accepted by the antenna to the power radiated by the antenna, and is thus higher than totoal efficiency if there is losses in strip line, components etc. The average gain in all directions is the same as the efficiency.
Polarization Circular Linear Small antennas have no clear polarization Reflection affects polarization Maximum power transfer requires polarization match between antennas in free space. In reality, polarization is not a problem.
MonopoleL- antenna F- antenna (Wire inverted F-antenna) PIFA (Planar inverted F-antenna) /4 - Pin Good, but very tall, 37 Ohm /4 - Pin Better, medium tall, but capacitivity to earth plane Move feeding point to 50 Ohm to create high inductance. High surface current = high power loss Create larger area to minimise surface resistance and power losses EVOLUTION 1.
Large In the middle of the antenna the Voltage = O v. That point is connected to earth and the antenna size is reduced by half. /4 - PATCH = PIFA /2 - PATCH EVOLUTION 2.
Microstrip Printed on PCB Low cost Although thin, quite large Depends on variation in board material Free space-dependent Narrow bandwidth
Application know-how & tuning Proven concepts Your strategic partner ! Complete antenna solutions Verification of antenna performance Antenna delivery
Your Benefit Shorter time to market Project support from A to Z High performance solutions
2.4 GHz antenna concepts for a wide range of applications SMD SWIVEL Snap-in ICM Laptop Instruments Dongles Head sets PCMCIA-cards Digital pens Mobile phones PDAs
External Concepts Swivel TITANIS Gain 1.6 dBi Efficiency:75% VSWR<1.5:1 Length :50 mm VIRAGO Gain 1.6 dB Efficiency:75% VSWR<1.5:1 Length :50 mm Basic data External 1/2 wave dipole Independent of ground plane with internal matching net Typical Applications Development kits, Prototypes, Printers, Instruments Customer benefits - Easy implementation - no matching & tuning - Perfect for feasibility studies - High performance - reliable data transfer - Designed for flexible mounting - rotating antenna blade
Internal concepts Snap-in CRISPUS Gain 1.6 dBi VSWR<1.5:1 Efficiency:73% Dim (mm) :20x30x4 FLAVUS Gain 1.4 dBi VSWR<1.4:1 Efficiency:62 % Dim (mm) :8x27x3 mm General Internal 1/2 wave dipole independent of ground plane with external matching Applications Mobile & desktop computers, Measuring instruments audio equipment, Automotive systems, Note books Customer Benefits - Easy & fast implementation - 1 working week - High performance - reliable data transfer - No soldering - Designed for pick & place - Proven concept
ICM concept General Internal Case Mounted antenna 1/2 wave dipole independent of ground plane with external matching, customized design of contact points and antenna. Applications PDAs, handheld devices, instruments, etc Customer benefit - High performance where space is restricted - Flexible mounting - type of fastening - Fast implementation compared to ceramic - Requires little space - only contact pad - Multi purpose antennas GHz & GSM ICM - Single band ICM - Multi Band ICM - Dual band
SMD concept MICA Gain 3-5 dBi VSWR<2.5 Efficiency:60% Dim (mm) :19x3.2x3.2 General Internal 1/4 wave PIFA dependent of ground plane. Applications Mobile & desktop computers, Measuring instruments audio equipment, Automotive systems, Note books Customer benefits - Easy and fast implementation - 1 week - Designed for SMD soldering - High performance - reliable data transfer - Small in size - Less sensitive than ceramic
Antenna selection Footprints Appli.notes samples Review of design & PCB Design of prototype Prototype ready Ramp-up STARTUPPROJECTPRODUCTION CUSTOMER gigaAnt Antenna selection guidance Review of PCB design Tuning & Matching Verification of prototype Final report Antenna delivery
Antenna delivery Antenna delivery Antenna specification Design of mechanical Interface Tuning in prototype Verification of prototype Transmission Line dimensioning Review of PCB design Matching in prototype Verification of prototype Transmission Line dimensioning Review of PCB design Tuning in prototype Verification of prototype Transmission Line dimensioning Custom. Tooling Review of PCB design Transmission Line dimensioning Antenna delivery Antenna delivery ICM SMD Ramp-up production Antenna delivery Snap-In Swivel Virago Swivel Titanis
Implementation issues Internal / External Standard or custom made Time schedule, estimated production volume, Available volume in device In-House or RF-Partner with know-how Required performance Space limitations Operating environment Continuous dialog Understanding for RF-problems Early access to chassis Early access to populated PCB
Antenna implementation: Standard concept Advantages Well known electrical performance Environmentally / mechanically tested Specifications and application note available Tools already manufactured Fast implementation Lower price Possible solution for low volume applications Disadvantages Hard to fulfill special requirements Size/Shape might not fit available volume optimal (form factor)
Common steps (RF point of view) Advice customer in antenna choices and placement Performance, Available volume, Hands… Review PCB-drawing for RF-mistakes Feeding (length, path, dimensions), Matching location, Ground plane, Through plating, Calculations… Build mock-up Antenna performance, Matching, Covers, Surrounding components, Hidden things… Final product Matching, Tuning, Measurements Report Antenna performance, Matching Follow up Antenna implementation: Standard concept
Advantages Meet special requirements Use all available volume in order to increase antenna performance Chance to start a new standard concept Disadvantages Uncertain antenna performance No documentation available Always a risk in new tools Uses lot of resources and time in organization Might only fit one application Costly in small volumes Antenna implementation: New concept
Common steps (RF point of view) Advice customer in antenna choices Build mock-up, often several in a developing process Check PCB for RF-mistakes Find subcontractor for tools, material, manufacturing Test products from subcontractors Order tools (prototype tool, soft tool, hard tool) Environmental test on parts from tools Changing tools After receiving PCB, matching and measurement Changes in PCB and covers are common Several reports during the process Follow up Antenna implementation: New concept
Ceramic Antennas Pros Small size Compact surface mount units Cons Large ground plane dependence -> high of non- working antenna Narrow bandwidth Low efficiency Hand sensitive
Mechanical design Parameters that affect performance Covers: Material, Shape, Colors, Metalisation Free space / Office environment Humans Stationary/mobile application Reflections from walls etc Environmental factors
Electrical design Parameters that affect performance Ground plane Position Surrounding components Transmission line dimensions Feeding (balanced/unbalanced) Matching Through platings
Strips Even if calculated to be 50 ohm, if too thin it introduces large losses due to distributed parasitic coupling to ground plane. Long strips should be avoided because of the high losses at 2.4 GHz in general FR-4. Sharp bend should be avoided because of the parasitic effects. Better to split up into two bends or a large radius. Some effects could be avoided if corner is chamfered.
Different type of strip lines Microstrip Stripline Co-planar waveguide Grounded co- planar waveguide
Antenna impact on the PCB Antenna require certan ground plane Or lack of ground plane Be aware of antenna user interaction RF close to radio chip because of feeding Area for matcing components Surrounding components (battery, contacts, cables, loudspeaker) Outside shielded areas
0dBm TX Power -40 dBm RX 1m -70 dBm RX 10m -90 dBm noise floor The actual sensitivity level is defined as the input level for which a raw bit error rate (BER) of 0.1% is met. The requirement for a Bluetooth receiver is an actual sensitivity level of –70 dBm or better. The receiver must achieve the –70 dBm sensitivity level with any Bluetooth transmitter compliant to the transmitter specification Specification requires -70dBm Some radio chips down to -90dBm The 10 meter range is not included in Bluetooth specification. Receiver characteristics
Friis transmission equation relates operating range, power and gain Hard partition office decreases range increases n Two antennas with 2 dBi gain Radio fulfilling -70 dBm. Antenna range
Network Analyser Measuring S-parameters in frequency domain VSWR, Return Loss, Smith Chart Phase Evaluate matching Evaluate undesired losses Coverage measurements
Determination of matching between the antenna and the transceiver in the prototype Essential to minimising power losses VSWR (Voltage Standing Wave Ratio)
VSWR Ideal 1:1 Typical 2:1 Minimized by matching network Power sent to the antenna should be accepted and not reflected.
Return Loss Used to describe antenna Related to VSWR Narrow / Spread band S11-parameter The analyzer sweeps frequencies and register reflection from antenna
Smith Chart Based on the result of Smith Chart measurements gigaAnt can carry out network matching Antenna Impedance Strip line impedance Smith Chart is used for matchinng and adjusting antennas
Transmission measurement Losses in feeding Losses in connections Isolation between antennas S12-parameter
Radiation pattern of the antenna when mounted in the actual device Needed to ensure the required functionality. It is easily seen if an antenna really is sufficiently omnidirectional or if a directional antenna has the expected radiation pattern. 3D radiation pattern
Field regions of antenna
3D radiation pattern measurement Anechoic chamber with shielding and absorbers Advanced controlling of probe position Two probes collecting both polarisations Network analyzer to collect data Nearfileld to farfield transformation Measure one frequency at the time DUT is rotating phi while probes are stepping theta.
Radiation Pattern Pattern from Bluetooth swivel under development measured in Moteco´s anechoic chamber. A 3D scan reveals things a 2D scan never could.
We verify compliance with national/international regulations SAR - (Specific Absorption Rate) = Tissue conductivity (S/m) E = Electric field strength in tissue (V/m) = Tissue dencity (kg/m 3 ) Governmental/ International agreement on how much a transmitting unit is allowed to heat tissue
SAR Not necessary for the 10 meter (1dBm) Bluetooth standard Necessary for the 100 (20dBm) meter Bluetooth standard Europe 2.0 mW/g over 10g cube tissue USA 1.6 mW/g over 1 g cube tissue SAR measurements are difficult Requires expensive and advanced equipment
Examination of the electrical and magnetic fields on the surface of the product (prototype) and antenna Important measurements the result is used during the development process to verify functionality and to ensure SAR compliance Field measurement
Summary Antenna Development Simulation is a useful tool, but not perfect The PCB is very essential to make a good antenna. Prototypes are an essential part of the development Continuous measurement and verification after changes in the surroundings Experience and know-how are important for a good result Iteration between design and measurement is needed
You need the right antenna to communicate ! What ?