Echoic Engineering

How do you select a particular transistor or technology for your microwave amplifier design??One of the critical metrics is the power gain at microwave frequencies.?There are actually a number of ways to define power gain depending on the situation. The S21 response will give a general idea of the gain at RF/microwave.?However, one must look at the transistor’s potential when matching networks are considered.?The transistor’s unmatched gate and drain impedances, determined by the semiconductor properties, are inherently different from the 50 ohms terminal impedances.?In ADS, we typically use the MaxGain() function to calculate the gain under the assumption of optimally matched conditions.?This gain is usually higher than S21 since the power match is improved by impedance matching. The projected maxgain also depends on the stability of the transistor.?When the stability factor K < 1, the device is stable under certain impedances and MaxGain() calculates the maximum stable gain (MSG).?When K > 1, the device is stable under all conditions (unconditionally stable) and MaxGain() calculates the maximum available gain (MAG). The “kink” in the MaxGain curve is actually due to the transistor going in and out of unconditional stability vs freq. The S21, Gmax, MAG and MSG of our FET model are shown.?The Gmax curve is a concatenation of MSG and MAG depending on if K is > 1 or < 1.?We can see that the Gmax curve follows the MSG or MAG depending on the underlying value of K. Echoic Engineering creates transistor level models and simulations for our client’s needs.?Free free to reach out to learn more! #gain #power #amplifiers #rf #microwave #rfengineering #rfic #mmic #poweramplifiers #PA #circuits #systems #integratedcircuits #technology #engineering #power #bandwidth, #stability #maxgain

EM simulation can help RF microwave designers visualize the behavior between connector and PCB. In our last post (https://lnkd.in/guZvK855), we demonstrated the EM simulation of a connectorized 50 ohm line which helped us understand the fields propagating through the device.?Here, we build upon that simulation to characterize the RF performance across frequency. In the animation, we can see energy flowing from one connector through the coplanar waveguide PCB structure to the connector at the other end.?This result verifies the configuration and helps us identify any anomalies (RF leakage, etc). This analysis is performed across frequency to extract the return loss (S11) and the insertion loss (S21) of the device.?A low S11 is highly desirable as it represents how much power is reflected from the incident connector and therefore how well matched it is to the signal generator.?A high S21 is desirable as this represents how much loss there is across the transmission.?A peak S11 of -10dB at 2GHz is acceptable but not great.?A minimum S21 of -0.6dB at 2GHz is also acceptable. EM simulations enable the designer to choose the appropriate connector design and PCB elements (trace widths, clearances, via density and placement) for high-performance, low loss connectivity. #connectors #impedance #PCB #rfsystems #rfic #mmic #rfengineering #rf #microwave #technology #microstrip #engineering #design #circuitdesign #circuits #em #electromagnetics #waves

The performance of edge-launch microwave connectors depends on their physical design and can vary wildly between manufacturer.?A well-matched connector providing a low-reflection transition from coax to planar is crucial for high performance microwave and millimeter-wave PCB designs.?This will result in low VSWR and return loss. Here we have two end-launch connectors mated to a PCB and electromagnetically simulated at 2GHz.?The simulation shows the fields as the signal propagates through the PCB. We are also able to visualize if the test board is behaving as expected. EM simulations enable the designer to choose the appropriate connector design and PCB elements (trace widths, clearances, via density and placement) for high-performance, low VSWR connectivity. #connectors #impedance #PCB #rfsystems #rfic #mmic #rfengineering #rf #microwave #technology #microstrip #engineering #design #circuitdesign #circuits #em #electromagnetics #waves

The Predistorter from our last two posts (https://lnkd.in/gZNgf98x) and (https://lnkd.in/gQ-Ef6cr) has already demonstrated marked improvement in enhancing PA linearity. Here, we put the Predistorter under our wideband noise power ratio test (https://lnkd.in/gg4T8c3a) to see how much improvement we can get.?Without the Predistorter, our PA only achieves NPR = 16dB at the output.?However, once we apply our Predistorter, that number increases to NPR = 22dB, a respectable 6 dB improvement! The use of the Predistorter has shown to provide linearity improvement in single-tone, two-tone and wideband multicarrier tests. Predistorter + PA improvement summary: ?P1dB = 17.5dB increased to 26dBm --> +8.5dB !! ?IIP3 = 14dBm increased to 26dBm --> +12dB !! ?NPR = 16dB increased to 22dB --> +6dB !! Echoic Engineering creates system level models and simulations for our client’s needs.?Free free to reach out to learn more! #noise #power #amplifiers #rf #microwave #rfengineering #rfic #mmic #poweramplifiers #PA #circuits #systems #integratedcircuits #technology #engineering #gain #power #linearity #nonlinearity #distortion #predistortion #gan

We had a lot of fun in Vegas learning about new technologies and challenges in the information space!

Noise power ratio (NPR) is an important method of measuring the linearity of a power amplifier (PA). A wideband, multi-carrier test signal is generated with one interesting feature – it is devoid of power over a very narrow subset of frequencies. The NPR is the ratio of the signal power outside to the noise power inside of the notch. Once passed through a PA, the power within the notch increases as a function of the PA’s noise and linearity performance. This is because nonlinearities in the PA generate intermodulation products which “fill in” the notch.?The result is a NPR which is far reduced from the input. In our PA example, the output NPR = 16 dB is a stark reduction compared to the input! Echoic Engineering creates system level models and simulations for our client’s needs.?Free free to reach out to learn more! #noise #power #amplifiers #rf #microwave #rfengineering #rfic #mmic #poweramplifiers #PA #circuits #systems #integratedcircuits #technology #engineering #gain #power #linearity #nonlinearity

Check out our new post on how the predistorter affects third-order intermods!

The two-tone test is widely used as a primary measure of linearity.?When a PA is excited with two signals of slightly offset frequencies, inherent nonlinear characteristics within the PA will generate third-order intermodulation products (IM3). From the swept-power IM3 responses, we can extract a linearity figure of merit called the third-order intercept point (IIP3 w.r.t. the input and OIP3 w.r.t. the output).?This imaginary point lies at the intersection between the extrapolated fundamental (slope=1) and IM3 products (slope=3). A predistorter can be applied to improve the linearity of a PA.?Our example PA alone has an IIP3=14dBm.?Using the same predistorter as in our last post, the IIP3 can be increased to 26dBm.?This concurs?with the single-tone linearity improvement that we saw in our last post. Echoic Engineering creates system level models and simulations for our client’s needs.?Free free to reach out to learn more! #amplifiers #rf #microwave #rfengineering #rfic #mmic #poweramplifiers #PA #circuits #systems #integratedcircuits #technology #engineering #gain #power #linearity #nonlinearity

Check out our new post on Predistorters for PA linearity!

As a power amplifier (PA) reaches its output limit, its gain starts to reduce.?A convenient point for identifying the onset of this limit is the 1dB-gain compression or P1dB point. Beyond P1dB, the amplifier is no longer considered linear and will exhibit poor performance on amplitude modulated signals, like QAM. One way to improve the linearity of the PA is to implement a predistorter at the input which will compensate for gain compression.?In effect, the overall gain characteristic will be “linearized” by extending P1dB to a higher output power. The single-tone analysis showing the AM-AM gain curve illustrates an 8 dB improvement of P1dB due to the Predistorter. Echoic Engineering creates system level models and simulations for our client’s needs.?Free free to reach out to learn more! #amplifiers #rf #microwave #rfengineering #rfic #mmic #poweramplifiers #PA #circuits #systems #integratedcircuits #technology #engineering #gain #power #linearity #nonlinearity