In this paper, we present a Ku-band 50 W internally-matched power amplifier that asymmetrically combines the power transistor cells of the GaN high electron mobility transistor (HEMT) (CGHV1J070D) from Wolfspeed. The amplifier is designed using a large-signal transistor cell model in the foundry process, and asymmetric power combining, which consists of a slit pattern, oblique wire bonding and an asymmetric T-junction, is applied to obtain the amplitude/phase balance of the combined signals at the transistor cell combining position. Input and output matching circuits are implemented using a thin film process on a titanate substrate and an alumina substrate with the relative dielectric constants of 40 and 9.8, respectively. The pulsed measurement of a 330 μs pulse period and 6% duty cycle shows the maximum saturated output power of 57 to 66 W, drain efficiency of 40.3 to 46.7%, and power gain of 5.3 to 6.0 dB at power saturation from 16.2 to 16.8 GHz.

In this paper, we demonstrate a compact 20-W GaN internally matched power amplifier for 2.5 to 6 GHz jammer systems which uses a high dielectric constant substrate, single-layer capacitors, and shunt/series resistors for low-Q matching and low-frequency stabilization. A GaN high-electron-mobility transistor (HEMT) CGH60030D bare die from Wolfspeed was used as an active device, and input/output matching circuits were implemented on two different substrates using a thin-film process, relative dielectric constants of which were 9.8 and 40, respectively. A series resistor of 2.1 Ω was chosen to minimize the high-frequency loss and obtain a flat gain response. For the output matching circuit, double λ/4 shorted stubs were used to supply the drain current and reduce the output impedance variation of the transistor between the low-frequency and high-frequency regions, which also made wideband matching feasible. Single-layer capacitors effectively helped reduce the size of the matching circuit. The fabricated GaN internally matched power amplifier showed a linear gain of about 10.2 dB, and had an output power of 43.3–43.9 dBm (21.4–24.5 W), a power-added efficiency of 33.4–49.7% and a power gain of 6.2–8.3 dB at the continuous-wave output power condition, from 2.5 to 6 GHz.

In this paper, we present a Ku-band low-loss traveling-wave power divider that uses a hollow substrate integrated waveguide (HSIW). For easy connection with microstrip-based devices and circuits, a low-loss transition between the microstrip line and the HSIW structure was implemented using C-cut via holes at the discontinuity interface, which reduces radiation and leakage effects and improves mismatch performance. To validate the performance of the transition, a back-to-back microstrip-to-HSIW transition was designed, fabricated, and measured from 12.5 GHz to 15.5 GHz. The measured results showed a return loss of 18 dB or more and an insertion loss of 0.5 ± 0.07 dB. An HSIW-based, low-loss 1:3 traveling-wave power divider was fabricated and measured from 13.5 GHz to 14.5 GHz. The power divider showed a return loss of at least 21 dB, an insertion loss of 0.57 ± 0.03 dB, and a power combining efficiency of 87.1%–88.3%.

Back-to-back 구조의 마이크로스트립 선로 입출력의 기판 집적 도파관 천이 구조는 12～18 GHz에서 20 dB 이상의 반사 손실과 1.5±0.2 dB의 삽입 손실이 측정되었고, back-to-back 구조의 빈 공간 기판 집적 도파관 천이 구조는 15 dB의 반사 손실과 0.55±0.2 dB의 삽입 손실이 측정되었다.

In this study, we designed and fabricated a 20-W internally matched gallium nitride(GaN) high-electron-mobility transistor(HEMT) power amplifier for an electronic warfare jammer in the frequency band of 2.5～6 GHz. The CGH60030D GaN HEMT from Wolfspeed was used as an amplifying device, and lossy matching was applied. An input series resistor that was used at the gate side for wideband matching reduced the amplifier's low-frequency gain and minimized high-frequency loss in the design frequency band. Input and output matching circuits were implemented on two different substrates whose relative dielectric constants were 40 and 9.8, respectively. The fabricated internally matched power amplifier showed a linear gain of approximately 11.5 dB, a power-added efficiency of 35.6～40.5 %, and a power gain of 7.2～8.8 dB at an output power of 20 W from 2.5 to 6 GHz.