摘要 |
<p>The invention relates to a frequency selective transformer circuit integrated on a multilayer printed board and operating at radio frequencies. To the input (1) of the transformer circuit there is coupled a resonant circuit realized by microstrip conductors (8, 9) operating as a two-pole filter. With the aid of the microstrip transformer according to the invention it is also possible to realize a mixer which attenuates the image frequency. <IMAGE></p> |