915M Filter for Power Spot transmitter

Reduced Jamming between Wireless Power Transmitter and Receiver by TEMWELL Bandpass Filter – 915 MHz

Wireless power transmission uses inductive technologies and is applied to various applications around in our life, for example, mobile and portable devices, audio-visual equipments, table-order-systems, robots, car-mounted devices, lighting and medical equipment etc. This technology has been commercialized for wireless charging of smart phone, tablet, mouse and keyboard, digital camera, wireless bracelet, digital TV etc.

For above application circuit designs are primarily operating in the unlicensed Industrial Scientific Medical (ISM) Band which adopted e.g. IEEE 802.11 (Wi-Fi), Bluetooth, ZigBee and RFID (NFC) wireless technologies. According to ITU Radio Regulations defined the ISM Band center frequency at 915 MHz, 433.92 MHz, 2.4 GHz and 5.8 GHz that are using in US, Europe and Asia countries.

The common method of wireless power transmission uses resonators to transmit electric power through the electromagnetic resonance between (Tx) transmitter and (Rx) receiver (magnetic resonant coupling). By matching the resonance frequency of both resonators with high Q factor, electric power can be transmitted over a long distance where magnetic coupling between Tx and Rx block is low. This way also offers flexibility in the receiver load location and the transmitter charging location.

In spite of benefits are great, there are many limitations and weak points necessitating the discussion of possible solutions. One of weak points is that in wireless transmission is extremely exposed to atmospheric noise and other signals, therefore the signal transfer from transmitter to receiver experience lots of attenuation losing and distortion.

An efficient solution without changing too much on design concept that is putting Bandpass Filter in the front-end blocks for filtering noise when signals received from transmitter throughout antenna, and signals received from external cable to connect from antenna to filter and filter to LNA. *If you need power amplifier or low noise amplifier Temwell sister brand Temstron can support please contact us 

Temwell RD team has developed high attenuation Bandpass Filter in standard ISM band centre frequency 915 MHz for reducing signal interference between wireless power transmitter and receiver. Please see the following models table, which Bandwidth includes from narrow 10 MHz to wide 120 MHz. The minimum Insertion loss less than 2 dB, high Attenuation can up to 60 dB depends on stop band you need. Return loss more than 12 dB. The linear waveform is excellent. Package offers two options, Pin and Connector (SMA or N), power sustain from 1 to 10 Watts. Small size for flexible locating in your design: Pin height 12.5mm, SMA connector height 26mm.