MBLCOUP models microstrip branch-line coupler (90o hybrid). Model is a general one, i.e. it allows arbitrary lengths and widths of feeding lines as well as of series and shunt arms.
|W1||Width of feeding line at ports 1 and 2||Length||W|
|W2||Width of feeding line at port 3 and 4||Length||W|
|W3||Width of the line connecting ports 1 and 2||Length||W|
|W4||Width of the line connecting ports 1,3 and 2,4||Length||W|
|W5||Width of the Iine connecting ports 3 and 4||Length||W|
|L1||Length of the line connecting ports 1,3 and 2,4||Length||L|
|L2||Length of the Line connecting ports 1 and 2||Length||L|
|L3||Length of the line connecting ports 3 and 4||Length||L|
L1. Series arm connecting ports 1,3 and series arm connecting ports 2,4 have the same length L1.
L2. Full length of shunt arm connecting ports 1 and 2.
L3. Full length of shunt arm connecting ports 3 and 4.
MBLCOUP uses MLIN and MSTEP (microstrip line and microstrip step of width) models, so all limitations of these models are applicable to MBLCOUP.
For equal split 3 dB coupler (equal power split and 90 0 phase shift between ports 3 and 4):
L1=L2=L3=λeff/4; (quarter of effective wavelength)
W4 provides characteristic impedance of series branches equal to 1/√2 times characteristic impedance of feeding lines.
Branch-line coupler with L2=L3 and L2≠L3 may provide more feasible design (see Reference ).
MBLCOUP implies that coupler is mirror symmetrical relative to horizontal axis (see Topology).
Feeding lines at ports may have different characteristic impedances. This is provided by proper choice of width parameters W1, W2 (see Topology).
To ensure specified power split, matching, isolation and phase shift between branched lines parameters may be derived in accordance with the recommendations in References , . However, user may set parameters to values of his choice or use them for circuit optimization.
This element does not have an assigned layout cell. You can assign artwork cells to any element. See “Assigning Artwork Cells to Layout of Schematic Elements” for details.
 Mongia, R., Bahl,I.J. and Bhartia P., RF and microwave coupled-line couplers, Artech House Inc., Norwood, MA, 1999, pp. 243-247