SPECIFICATION Part No. : HA.31.A Description : 915MHz 2dBi Embedded Helical Monopole Antenna Features : Quarter wave-length Monopole Helical Antenna 915MHz ISM Band 2dBi peak gain and 68% efficiency Direct mounted on board design Mechanically sturdy in a compact size Dimensions: 10.7mm, Ø10.
1. Introduction The HA.31.A is an ISM 915MHz quarter wave-length monopole antenna. This helical coil antenna is perfect for your smart meter, smart security system, remote asset monitoring, and other wireless communication devices. The helical coil antenna has a 2dBi Peak gain and a 68% efficiency at 915MHz on a 126.8 x 80.1mm ground plane with matching components (orthogonally mounted to ground plane, see HAD.B.31 performance).
Taoglas provides HAD.A.31 and HAD.B.31 evaluation boards to show performance when two antennas are parallel mounted or orthogonally mounted to the ground plane. Small embedded antennas can easily detune and/or have reduced efficiency in different device environments. Taoglas provides matching, and other custom tuning, design and support services, subject to MOQ and NRE. Contact a regional Taoglas facility for details.
2. Specification ELECTRICAL Application Bands ISM 915MHz Mounting Direction Frequency (MHz) HAD.A.31 902 915 HAD.B.31 928 Return Loss (dB) 902 915 928 <-10 Peak Gain (dBi) 0.41 0.05 -0.74 1.89 2.09 2.04 Average Gain (dBi) -3.14 -3.30 -4.05 -1.74 -1.61 -1.65 Efficiency (%) 48.51 46.73 39.28 66.95 68.94 68.37 Polarization Linear Impedance 50 ohms MECHANICAL Helical Coil Dimension (mm) L: 10.7mm, Ø10.2mm Weight (g) 0.
3. Antenna Characteristics 3.1 Return Loss 3.
3.3 Average Gain 3.
4. Antenna Radiation Pattern 4.1. Measurement Setup The HA.31 antenna is tested on HAD.A.31 and HAD.B.31in a CTIA certified ETS-Lindgren Anechoic Chamber. The test setup is shown below.
4.2. 2D Radiation Pattern - On HAD.A.
YZ Plane Z Y - On HAD.B.
- XZ Plane Z X - YZ Plane Z Y DSP-15-8- SPE-16-8-017/D/WY Page 10 of 24
4.3. 3D Radiation Pattern - On HAD.A.31 @915MHz - On HAD.B.
5. Mechanical Drawing (Unit: mm) 5.1 HA.31.
5.2 HAD.A.
5.3 HAD.B.
6. Packaging 6.1. HA.31.
6.2. HAD.A.
6.3. HAD.B.
7. Antenna Application Note 7.1 Matching Circuit for Different Ground Plane Variation 7.1.1 HAD.A.31 EVB Board HAD.A.31 Ceramic 4 Ceramic 5 Ceramic 6 160mm 0 ohm 3pF 1.5pF 150mm 0 ohm 3.3pF 1.5pF 140mm 0 ohm 3.6pF 1.5pF 130mm 0 ohm 3.9pF 1.5pF 120mm 0 ohm 3.9pF 1.5pF 110mm 0 ohm 3.9pF 1.5pF 100mm 0.5pF 2pF 1.5pF 90mm 0.5pF 1pF 1.5pF 80mm 0.5pF open 5.1nH 70mm 0.75pF open 3.9pF 60mm 0.75pF open 2.7pF 50mm 1pF open 1pF 7.1.1 HAD.B.31 EVB Board HAD.B.
7.2 Return Loss 7.2.1 HAD.A.31 EVB Board (Different Ground Lengths) 7.2.2 HAD.B.
7.3 Efficiency 7.3.1 HAD.A.31 EVB Board (Different Ground Lengths) 7.3.2 HAD.B.
7.4 Average Gain 7.4.1 HAD.A.31 EVB Board (Different Ground Lengths) 7.4.2 HAD.B.
7.5 Peak Gain 7.5.1 HAD.A.31 EVB Board (Different Ground Lengths) 7.5.2 HAD.B.
7.6 Antenna Performance Table ELECTRICAL Application Bands ISM 868MHz Mounting Direction Frequency (MHz) HAD.A.31 902 HAD.B.31 915 928 902 915 928 Efficiency Ground plane length 160mm 50.92 47.74 35.70 54.59 57.56 56.01 Ground plane length 150mm 52.62 49.34 38.06 57.57 58.93 56.60 Ground plane length 140mm 51.00 47.03 36.57 63.01 60.90 54.24 Ground plane length 130mm 50.09 48.24 39.18 65.03 60.52 51.18 Ground plane length 120mm 48.20 45.61 36.69 63.62 58.40 48.
Peak Gain(dBi) Ground plane length 160mm 1.37 1.13 -0.19 0.62 0.87 0.74 Ground plane length 150mm 1.33 1.02 -0.18 0.62 0.79 0.59 Ground plane length 140mm 0.94 0.58 -0.42 0.99 0.90 0.40 Ground plane length 130mm 0.75 0.67 -0.12 0.89 0.66 -0.02 Ground plane length 120mm 0.45 0.29 -0.54 0.67 0.37 -0.41 Ground plane length 110mm 0.15 -0.04 -0.78 0.42 0.05 -0.72 Ground plane length 100mm -0.29 -0.40 -0.97 -0.15 -0.66 -1.60 Ground plane length 90mm -0.26 -0.
