A design of octagon‐shaped 3‐dB ultra wideband coupler using multilayer technology

Abstract

A design of a 3‐dB ultra wideband (UWB) coupler with compact size (35 mm × 15 mm), which operates between 3.1 and 10.6 GHz is presented in this article. The proposed design is accomplished by using multilayer microstrip structure, which is formed by three layers of conductor and two layers of substrate. The top and bottom layers consist of an octagon‐shaped microstrip lines and an octagon‐shaped slot in the middle layer. The design was fabricated on Rogers RO4003c substrate. Both of the simulation and measurement results are being compared with verify the coupler's performances in real environment. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:127–130, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27259

A compact ultra‐wideband quadrature hybrid based on coupled‐line phase shifter and power divider

“…Because the bottom metal base for heat dissipation and electromagnetic (EM) shielding have to keep away from it. The same problem also appears in to . Third, the single‐layer edge‐coupled microstrip couplers feature simple structure and low cost, but the bandwidths are less than 25% .…”

“…In general, the quadrature hybrids can be implemented by the 3‐dB coupled structures, such as the branch‐line couplers , three‐layer broadside‐coupled microstrip/slot couplers , two‐layer coupler with slotted ground plane , and single‐layer edge‐coupled microstrip couplers . Apart from these four‐port couplers, the quadrature hybrids can also be realized in the three‐port structure, which comprises a Wilkinson power divider and a 90° phase shifter .…”

“…However, it should be noted that the cascaded multisection structure occupies large circuit area. Second, the broadside‐coupled microstrip/slot couplers can operate over ultra‐wideband, but the three‐layer structures may cause incompatibility with other components during circuit integration . The slotted ground plane of the two‐layer coupler is used to achieve the 3 ± 1 dB coupling coefficient between the edge‐coupled microstrip lines over wide band .…”

Improving isolation of slot‐coupled directional couplers with weak and tight couplings

“…The slot-coupled directional couplers with the elliptical-shaped slot and patches were first proposed to cover the ultra-wide frequency band [8]. Since then, many attempts have been made to improve the performance of the slot-coupled directional couplers by employing patches and slots with different shapes, different substrate heights or different substrate permittivities [9][10][11][12][13][14][15][16][17][18][19][20]. In [9], two different functions have been considered to represent the tapering of the patches and the slot of the slot-coupled directional couplers and the effect of this tapering has been studied.…”

“…In [9], two different functions have been considered to represent the tapering of the patches and the slot of the slot-coupled directional couplers and the effect of this tapering has been studied. Other attempts have studied the performance of the slot-coupled directional couplers that use slots and patches in other shapes such as diamond, contoured, trapezoidal, bezier curve, octagon, butterfly and mountain [10][11][12][13][14][15][16]. Some other references discuss the combination of different geometrical shapes for the slots and the patches [17][18][19].…”