Excellent GaN PA recommendation, please take a look if you are interested.

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Excellent GaN PA recommendation, please take a look if you are interested. [Copy link]

Qorvo's new enhanced mmWave Spatium amplifiers deliver exceptional combined efficiency and bandwidth in a compact envelope for high-performance applications such as satellite ground base stations, 5G infrastructure, radar and electronic warfare.

Let’s take a look at these two products below.

QPB2731: Provides 100 W output power in the 27-31 GHz frequency range.

QPB3238: Provides 100 W output power in the 32-38 GHz frequency range.

The two solid-state power amplifiers (SSPAs) can handle continuous wave (CW), pulsed and modulated RF waveforms and have two bias options to meet application requirements.

Like previous Spatium technologies, mmWave Spatium uses a laminated antenna structure that allows 16 elements to be integrated in a quasi-transverse electromagnetic (TEM) coaxial environment. In theory, this allows the SSPA to deliver 12 dB more power than each MMIC.

Before building the amplifier, Qorvo designed a passive structure to evaluate the performance of the combined network to replicate the amplifier RF path without the MMIC. At the input, the RF signal enters through a 2.92 mm female connector and is physically expanded within an oversized coaxial area to a laminated, end-fire antenna array that splits the RF signal into 16 equal signals, each with a microstrip transmission line connected to the MMIC input (see Figure 1).

However, in the passive structure, the microstrip transmission line is connected to another laminate antenna array that is reversed at the input. In most cases, the output of the high power amplifier (HPA) requires an output connection with appropriate power handling capabilities, such as a WR28 waveguide. A 2.92 mm female connector is used at the output of this passive test structure for a broadband connection to a standard network analyzer.

Each laminate is soldered to a silver-plated copper blade to form a 1/16 wedge when viewed along the major axis.

AGC Taconic TLY-5Z was selected as the core laminate material because it has a low dielectric constant (εr=2.2) and a relatively low dielectric loss tangent (tanδ=0.0015 at 10 GHz), which helps achieve broadband, low-loss performance of the antenna structure.

Although the metallization on the passive laminates is covered with an IPC-compliant layer of immersion silver to prevent copper oxidation, amplifier designs typically use gold plating to be compatible with gold wire bonds on the MMIC.

Figure 2. Comparison of simulated and measured values of passive component insertion loss (a) and return loss (b).

The passive structure is designed and analyzed using ANSYS HFSS. The comparison between the simulated and measured values of the passive structure insertion loss and return loss is shown in Figure 2.

Although there is a small deviation between the measured values (red line) and the simulated values (blue line), the correlation is generally good and the observed performance can be used for amplifier development. The insertion loss measurement reflects the loss of the entire RF path, that is, the input and output losses. In the SSPA, the MMIC is placed toward the output, so that more than 50% of the microstrip transmission line precedes the MMIC. Therefore, a reasonable estimate of the output insertion loss is 0.67 dB, which can achieve a combined efficiency of 86%.

Figure 3 Typical output power and PAE of QPA2211 (a) and TGA2222 (b).

In the QPB2731 design, Qorvo's QPA2211 GaN MMIC was selected as the HPA. The QPA2211 is designed to provide 14 W saturated output power and 5 W linear CW output power, achieving 34% power added efficiency (PAE) under CW operation (see Figure 3). In the QPB3238N design, the TGA2222 GaN MMIC was selected as the RF HPA; it is specified to have a CW saturated output power of 40.2 dBm, a PAE of 22.3% in the 32-38 GHz frequency range, and a die backside temperature of 25°C (see Figure 3). Both devices are produced using Qorvo's 0.15μm GaN on SiC process (QGaN15).

Figure 4. Output power and drain efficiency measurements of the QPB2731 (a) and QPB3238 (b) at 25°C clamping temperature.

Aren’t these two PAs very good? This is a detailed introduction given by Qorvo on GaN PA that can provide 100W output power in the 27-31 and 32-38GHz frequency ranges . Friends who are interested can take a look. Good chips are used in good products to enhance product competitiveness.