For higher bandwidth, try a matched delay or Guanella type (the type shown above is Ruthroff).
This is constructed by wiring transmission lines in parallel at one end, and series at the other. That is, consider a TL as a common mode choke. By arranging some series-parallel combination on one end of a set of TLs, and a different series-parallel combination on the other, you can get any rational ratio you like (though going beyond quite small values of p, q (for ratio p/q) is rather bothersome).
By considering the CM voltages on each TL segment, and connecting them appropriately in each S/P stack, the number of turns for each TL on a common core can be determined.
For example, for a 9:1, you'd use 3 TLs in parallel on one side, wired in series on the other side. Use Zo = 150 ohms, so the parallel combo presents 50 ohms to the source, and the series combo presents 450 ohms to the load. The bandwidth is limited only by the TL width (i.e., breakup into higher TE/M modes) and how tightly you can arrange the parallel/series connections. Only real delay is added, which as usual manifests as leakage inductance at LF, but does not incur the roll-off at HF that the mismatched delays of the Ruthroff design has.
Tim