Browsing by Subject "SPDT"

Now showing 1 - 3 of 3

Open Access
High-power and low-loss SPDT switch design using gate-optimized GaN on SiC HEMTs for S-band 5G T/R modules
(2022-07) Ertürk, Volkan
Radio frequency (RF) switches are one the fundamental components of modern communication systems. They enable the routing of high-frequency signals into different transmission paths. Therefore, they play a crucial role in transceiver (T/R) modules. Especially, 5G technology creates a demand for compact switches with high power handling, high isolation, and low insertion loss. GaN on SiC high electron mobility transistor (HEMT) technology stands out with its exceptional electrical and thermal characteristics among other semiconductor technologies. However, switch performance is limited by selected topology and transistor capability. Notably, the T-gate dimensions of the HEMTs directly affect the small-signal and large-signal performance of the switch. This study focuses on designing a single-pole double-throw (SPDT) monolithic microwave integrated circuit (MMIC) switch using gate-optimized HEMT in AlGaN/GaN on SiC technology. The foot length of the gate is varied from 200 nm to 250 nm, and the head length is varied from 500 nm to 750 nm in the T-gate structure to optimize the RF performance. An asymmetric SPDT switch using transistor with 500 nm head length and 250 nm foot length is designed to demonstrate transistor performance. The switch achieved an insertion loss of better than 0.85 dB throughout the 3.2–3.8 GHz bandwidth. The low-noise path can handle 25 W power level, while the high-power path can withstand up to 50 W of RF power at 1 dB compression level. The isolation performance is about 25 dB, while the return loss of the switch is better than 12 dB. The switch occupies a chip area of 2 x 2.2 mm2.
Open Access
X-band high power GaN SPDT MMIC RF switches
(IEEE, 2019) Osmanoğlu, Sinan; Özbay, Ekmel
This paper describes the design results and measured performance of three different high power, low loss and high isolation GaN high electron mobility transistor (HEMT) based single-pole double-throw (SPDT) RF switches. Three different topologies were employed to design the proposed switches. The SPDT MMIC switches were developed with coplanar waveguide (CPW) GaN-HEMT technology to operate in X-Band. The measured performance showed that the switches have typical insertion loss of better than 2 dB, higher than 30 dB isolation with better than 10 dB return losses.
Open Access
X-band low phase noise mmic vco & high power mmic spdt design
(2014) Osmanoğlu, Sinan
Generally the tuning bandwidth (BW) of a VCO is smaller than the tuning BW of the resonant circuit itself. Using proper components with right topology can handle this problem. In order to overcome this problem and improve the tuning BW of the VCO, common-base inductive feedback topology with Gallium Arsenide (GaAs) Heterojunction Bipolar Transistor (HBT) is used and an optimized topology for tank circuit is selected to minimize the effect of bandwidth limiting components. Designed VCO with this topology achived -117 dBc/Hz at 1 MHz offset phase noise with 9-13 dBm output power between 8.8-11.4 GHz band. Second part of the thesis composed of Single Pole Double Throw (SPDT) RF Switch design. From mesa resistors to SPDT fabrication, everything is fabricated using Bilkent University NANOTAM Gallium Nitride (GaN) on Silicon Carbide (SiC) process. Switching HEMTs are fabricated to generate a model to design SPDTs and the final design works between DC-12 GHz with less than 1.4 dB insertion loss (IL), -20 dB isolation and 14.5 dB return loss (RL) at worst case. The power handling of the switches are better than 40 dBm at output with 0.2 dB compression, which is measured with continuous wave (CW) signal at 10 GHz.