Browsing by Subject "Wilkinson power divider"

Now showing 1 - 3 of 3

Open Access
Compact and wideband CPW wilkinson power dividers for GaN MMIC applications
(IEEE, 2018) Sutbas, Batuhan; Özbay, Ekmel; Atalar, Abdullah
This paper presents two types of modified CPW Wilkinson power dividers at X-band using GaN MMIC technology on a SiC substrate. Lumped element equivalents of the transmission line arms are used and they are capacitively loaded to achieve a reduced circuit size of lambda/14timeslambda/8. A symmetrical series RLC circuit in the isolation network is used to compensate for the bandwidth degradation after circuit miniaturization maintaining a fractional bandwidth of 29 % for input/output return losses and isolation better than 20 dB with an extra insertion loss less than 0.35 dB.
Open Access
Improved Wilkinson power divider structures for millimeter-wave applications
(2019-01) Sütbaş, Batuhan
Communication systems, radars, electronic warfare and space applications desire integrated circuits with higher operating frequencies. Working at the millimeter-wave region increases data rates, provides a more efficient use of the spectrum and enables smaller products. Power dividers are used as building blocks for such applications to split and combine RF signals. Wilkinson power divider is one of the most commonly used topology, providing high return loss and isolation with low insertion loss. However, it occupies valuable chip area, has a limited bandwidth, requires accurate modeling and precise fabrication. In addition, the layout becomes complicated for three or more outputs and cannot be realized on a planar circuit. This work presents three techniques to address the drawbacks of the original Wilkinson divider. The first structure achieves a compact size without bandwidth degradation and provides additional physical isolation at the output. The second divider improves the bandwidth of operation and increases tolerance to sheet resistance variance, enabling robustness and higher yields. The third technique simplifies the layout of three-way dividers and allows a planar fabrication technology. The proposed structures are analyzed using even-odd mode analysis and design equations are derived. Three high performance dividers with 30 GHz center frequency are designed employing the developed methods. The circuits are realized using GaN based coplanar waveguide and microstrip monolithic microwave integrated circuit technology. Experimental results demonstrate good agreement with theory and simulations, proving that the presented improvements could be useful in future millimeter-wave RF applications.
Open Access
X-band CPW high power amplifier design by GAN based MMIC technology
(2016-06) Yılmaz, Burak Alptuğ
The developments in defense industry, telecommunication and satellite systems have gradually increased the necessities for the small and compact Power Ampli- fiers (PAs) with high output powers and gains. Monolithic Microwave Integrated Circuits (MMICs), that are fabricated by using Gallium Nitride (GaN) on Silicon Carbide (SiC) substrate, achieve the system requirements. GaN based MMIC technology gives chance to produce high power capable and compact PAs. Moreover, suitable Wilkinson Power Dividers (WPDs) with low Insertion Loss (IL) assist in transferring output power of the device with combining MMIC PAs. Presented designs in this thesis work have been fabricated in Bilkent University NANOTAM with GaN on SiC process. Fabricated X-band Coplanar Waveguide (CPW) PA works from 7.9 GHz to 8.4 GHz as intended and its efficiency equals to 40 % at 8.4 GHz under 2.1 dB compression. Measurements of fabricated PA show that output power of the device is equal to 37.8 dBm under 2.1 dB compression and it has 9.8 dB minimum gain in the operating band. Furthermore, equal, three-way WPD device was designed and fabricated with the same process and it works at wide-band range with approximately 0.9 dB IL. It is advantageous that the total dimension of paralleled MMIC PAs can be adjusted by scaling branches of the designed WPD with the aim of performance optimization.