A practical technique for designing multiport coupling networks

Optimal noise matching condition for mutually-coupled antenna arrays

“…A significant amount of work has already been done on designing and realizing decoupling networks [1,2,11]. While this work is important and will likely find use in some applications, complex matching networks are difficult to realize and introduce undesirable loss and therefore increase the system noise figure.…”

Characterizing Optimal Multiport Matching Transformers

“…Consequently, orthogonal transformers simplify design problem by mapping the coupled the physical ports to the uncoupled eigenports [12]. Figure 6 shows how two standard 1 × 1 transformers can realize a SIMO transformer.…”

“…For perfect matching, this is the "compatible impedance problem" explored by Youla, Carlin, and Yarman [24,25]. Specific to transformer matching, Geren, Curry, and Andersen offer a design process using orthogonal transformers to decouple the physical ports that simplifies the matching problem [12]. The complex transformer offers another approach for matching a complex generator to a complex load at a single frequency [10], [18, (2.26)].…”

“…Geren returned to this topic in 1996 and gave a design procedure for decoupling the resistive and reactive parts [12]. In 2006, Gan's Ph.D. thesis examined wideband transformer design for on-chip applications [11].…”

On the design of wideband and tunable matching and decoupling networks for N-port antennas

“…The classical solution approach, which was derived in the application context of classical (regular) antenna arrays leads to a MDN which comprises a cascade connection of a 2N -port decoupling network, constructed from hybrids, with N two-port matching networks [3], [5], [6]. As it will be shown in Section II this approach cannot be applied to wideband or multi-band N -port antenna systems on small devices.…”