Question

benefits of miniaturization of electronic components

Answer 1

Branch-line couplers are widely used in various SHF devices, such as power splitters, power combiners, phase shifters and many others. A branch-line coupler is a device with four inputs designed to divide power equally between its two outputs wherein the remaining output is left loose. When designing new microstrip branch-line couplers, engineers usually try to raise the manufacturability and to reduce geometrical dimensions. Lately great attention has been paid to the last factor, especially when using a device at low frequencies. Currently there are many solutions for the branch-line couplers miniaturization [1]–[13]. For instance, this paper [1] introduces the dimensions reduction with the help of quasi lumped elements, periodic capacity load [2], irregular T-shaped structures [3], wave-slowing structures [4], [5], fractal structures [6], high-ohmic structures [7], loaded lines [8], interdigital condenser [9]. The latest researchers' papers are also related to the designing of traditional compact micro strip branch-line couplers [10]–[12]. All of the listed ways have its benefits and drawbacks. Thus, nowadays the problem of designing the compact branch-line coupler while keeping its characteristics similar to the traditional construction is still of great interest. This article contains research on advantages and disadvantages of the miniaturization method based on the replacement of the micro strip transmission line section by a low pass filter with the same phase shift as the one of the replaced section.