Increase the Wireless Transmission Distance Between VNA and SAW in PXIE-S5090

Issue Details

The Device Under Testing (DUT) is surface acoustic wave (SAW) sensor (Resonance type). The transmitted signal of the Vector Network Analyzer (VNA) is transmitted to the Interdigital electrode of surface acoustic wave sensor (SAW) via the antenna.

After the interdigital electrode receives the electrical signal, it will excite the surface acoustic wave vibration in the piezoelectric sheet below it. The vibration is reflected by the reflection grids on both sides and then transmitted back to the Interdigital Transducer (IDT).

This vibration is converted into electrical signals in the interdigitating electrodes. The electrical signal is retransmitted back to the VNA via the antenna.

I want to measure S11 and S21 by using PXIE-S5090. However I found that the wireless transmission distance (VNA and SAW) is shorter than I expected. Is that anyway to increase the wireless transmission distance?

Solution

The wireless transmission distance can be added by increase the power range of PXIE-S5090.

For example, the default power range of test port output (300 kHz to 6.5 GHz) is +13 to +15dBm, assume that increase to +20 to +30dBm can fulfilled the distance requirement, and external power amplifiers can be connected to PXIE-S5090.

However, amplifiers are one way devices which means that the signal can be amplified in one direction. This characteristic will cause the Rx signal to fail to pass through the power amplifier in the reverse direction, so the S11 not able to be measured.

When measuring S21, the external couplers are needed to measure the reflection from the Antenna. The port 2 to receive reflected signal is needed because PXIE-S5090 don't have direct receiver access (DRA). Measurement setup does not have to be this with DRA VNAs.

Based on how much power the coupler couples to the port 2, need optional attenuator to make sure VNA does not compress or be damaged. With this setup, the S11 measurement of antenna will be S21 on the VNA.
 
 

Additional Information

1. Does the power amplifier have special requirements to match the VNA? Has there been any such use case in the past?
   The power amplifier should match the needs of the Device Under Test. There are no special requirements for the power amplifier to match the VNA.

 

2. The output power of the power amplifier is relatively high. Will it cause damage to the 2-port if it is directly connected to the 2-port?
   To avoid any damage to the VNA, either a 10dB or higher dB attenuators/pads can be used based on the output power of your amplifier.