A Compact Wide-Band Rat-Race Hybrid Using Microstrip Lines

A Design of Branch-Line Coupler with Harmonic Suppression and Size Reduction Using Closed-Loop and Open-Loop Resonators

“…Harmonic Suppression Size reduction [1] No 0% [2] 2nd 72% [3] No 55% [4] No 63.9% [5] No 60% [6] 2nd 73.2% [8] 3rd 65% [9] No 69% [10] No 62% [11] No 37% This work 2nd & 3rd 41%…”

“…Furthermore, the conventional branchline coupler is not capable of suppressing spurious frequencies. In order to overcome these defects, various methods have been reported in [2][3][4][5][6][7][8][9][10] so far. In [2], a slow-wave branch-line coupler using high-low impedance resonators is designed.…”

“…Unfortunately, EBG and DGS need etching process at both sides and they cannot be utilized on metal surface. A compact microstrip rat-race hybrid employing spacefilling curves is reported in [9], and the proposed circuit occupies 31% of the area of the conventional design. However, the employed curves have not suppressed any spurious frequencies.…”

Dual Composite Right/Left-Handed Leaky-Wave Structure for Dual-Polarized Antenna Application

“…In order to realize the input excitations depicted in Section 2, a broadband two-section 3-dB rat-race hybrid is designed and fabricated [17]. The hybrid is fabricated on the Rogers 5880 substrate with a thickness of 0.254 mm and a relative permittivity of 2.2.…”

Multiband Aperture Slot Microstrip Patch Antenna With DGS for Bandwidth Enhancement

“…The CM current component naturally introduced as noise when we use Vivaldi antenna fed by differential signal given by rat race coupler [13] This system (filter-antenna) with CM noise rejection for wide band around 125% from 2 to 10 GHz is presented which is required for radio astronomical observations. This system is built from two component circular aperture slot antenna differentialy fed & DGS technology which is filter based.…”