In this paper an edge coupled microstrip coupler with defected ground structure is presented. A normally 7 dB coupler designed on Alumina substrate is converted into a 3 dB coupler by cutting single rectangular slot in the ground plane encompassing the two transmission lines. Other properties of backward wave coupler remain the same, except for a tighter coupling. With this method of design opt...

Using the even-odd mode anafysis of four-port networks with double symmetry, the scattering parameters of the microstrip-slot coupler are derived from the evenand odd-mode parameters of the coupler cross section. The uncompensated coupler and the coupler compensated by extending tbe slot fines are treated and desigo specifications are given covering the compensation slot lines. A comparison wit...

A topology for a 3-dB broadband and small-size ring coupler is proposed. It consists of fully-distributed Composite Right-/Left-Handed phase shifters and a Lange coupler. For the fabricated coupler, the frequency bandwidth is one octave, centered on 1.5GHz, while the footprint area is reduced to 25%, compared to the conventional ring coupler topology. The experimental results are in good agreem...

A new method to design a miniaturized ring coupler consisting of multiple open stubs on the inside of the ring is proposed. It is shown that this coupler topology may be seen as fully-distributed composite right/left handed (CRLH) small-size phase shifters, cascaded in a ring configuration. The CRLH phase shifter is analyzed in detail and a design method is proposed, pointing out the condition ...

A method to improve the directivity of the microstrip coupler is presented. The width of the coupler is modified for phase velocity compensation which results in high directivity. Using this procedure, a 15 dB coupler is designed and simulated at 0.9 GHz using SONNET software. A high directivity of 46 dB is obtained. The validity of the design concept is verified and compared with conventional ...

A new shaped circularly polarized dielectric resonator antenna (CP DRA) is studied with branch-line coupler and log-periodic balun for the GPS application. Since the coupler and balun are located under the DRA, it does not increase the footprint of the antenna, as a result the system is very compact. Two configurations are considered in this paper. In the first configuration, an external 50Ω lo...

An impedance-transforming lumped-element (LE) two-branch 90 coupler is discussed in this paper. The LE coupler discussed here can be derived from a branch-line coupler consisting of one-quarter or three-quarters wavelength transmission-lines (that is, case of type C) and classified into five groups. Normally, the LE coupler needs 8 circuit elements. However, the existence of reduced LE couplers...

A single stage quadrature hybrid coupler with enhanced flat balance over a wide bandwidth is presented in this article. The present coupler is realized by replacing the transmission line sections of the conventional two-branch coupler by their equivalent parallel coupled microstrip lines (PCML). The impedance controlled wide-bandpass response produced by the PCML is utilized to achieve flat bal...

This paper proposes a compact and miniaturized branch-line coupler using a crossing bond wire structured slow-wave branch line (CBWSWB). The proposed coupler achieves a size reduction of 82% compared with a conventional implementation. Measured S11, S21, S31 and S41 of the proposed coupler are better than −24, −3.7, −3.7 and −28 dB at 3GHz, respectively. Furthermore, the phase difference betwee...

A novel microstrip Coupler with Complementary SplitRing Resonator (CSRR) is simulated and fabricated. The CSRR structure in the grounded plane of a conventional microstrip double-line coupler, increases its even mode characteristic impedance. This results in a higher degree of coupling. The results of simulation and measurement show that the new coupler achieves a high degree of coupling (5 dB ...