A Broadband Gain Amplifier Designed with the Models for Package and Diode Using 0.5 μm GaAs E-pHEMT Process

This paper presents a 50 MHz to 5 GHz broadband gain amplifier using a 0.5 μm gallium-arsenide pseudomorphic high-electron-mobility-transistor (GaAs pHEMT). For broadband design, a high gain cascode structure with a feedback network was used. To ensure the robustness of the design, the amplifier had to consider the effects of the Electrostatic Discharge (ESD)-protected diode and the package, which can degrade the broadband performance. Therefore, the equivalent circuit models of the package and the ESD-protected diode were analyzed and simulated in this paper. The designed broadband gain amplifier from 50 MHz to 5 GHz frequency band has a die size of 700 μm x 1000 μm and consumes 156 mW of dc power, and it was simulated with a gain of 18.7 dB to 20.6 dB, a P1dB of 15.3 to 16.9 dBm, and a OIP3 of 26.5 to 31 dBm. Furthermore, the excellent gain flatness exhibited within 18.7 dB ± 1.92 dB at the interest of the frequency band.

Broadband gain enhancement of an UWB antenna using conformal wideband NRI metamaterial

In this article, broadband gain enhancement of an ultra-wide band (UWB) antenna is achieved by using 4 × 4 array of a wideband negative refractive index (NRI) metamaterial as a reflector layer. A novel shaped metamaterial sized 14.8 × 14.8 mm2 with double negative (DNG) characteristics in three frequency regions has been fabricated on a flexible FR4 with 0.25 mm thickness. The proposed metamaterial gives a continuous NRI bandwidth of 10 GHz (2–12 GHz). The effective parameters of the unit cell cover S, C, X, and Ku-band independently and show DNG region of 6.1 GHz at C (4–8 GHz) and X band (8.8–10.5 GHz, 11.2–11.6 GHz). The unit cell structure is also found to be feed insensitive. The unit cell has small volume of 54.76 mm3 along with flexible nature which makes it suitable for wearable applications. For a 4 × 4 array the metamaterial still exhibits DNG characteristics. To understand the physical behavior of the unit cell, the circuit analysis along with the study of magnetic and electric field distribution at three resonance frequencies (2.2, 8.2 and 14.2 GHz) is done. Both simulation and measured results indicate that the gain and bandwidth of metamaterial antenna are enhanced by 2 dB and 0.8 GHz.