Switchable Diplexer With Physical Layout To Provide Improved Isolation

Abstract

A switchable diplexer includes a plurality of bandpass filters having passbands for the frequency bands in which communication across a communication channel is desired. The bandpass filters can be arranged in groups of bandpass filters located adjacent to one another physically. Further, a group of bandpass filters can include a plurality of bandpass filters having a stop band in a common frequency range of interest. A plurality of switches can be provided to switch the desired bandpass filter into the circuit to allow communication on its corresponding band. The switches can therefore be electrically coupled to the passband filters and configured to select one of the plurality of bandpass filters for signal communication on the communication channel.

1 . A switchable diplexer, comprising:
 a plurality of bandpass filters, the bandpass filters having a predetermined passband; and   a plurality of switches coupled to the passband filters;   wherein:   the bandpass filters are arranged in groups of bandpass filters,
 a first of said groups comprising a first bandpass filter having a passband in a first frequency range and a second bandpass filter having a passband in a second frequency range that at least partially overlaps the first frequency range, the first bandpass filter and the second bandpass filter being electrically arranged in parallel relation to one another, and 
 a second of said groups comprising a third bandpass filter having a passband in a third frequency range and fourth bandpass filter having a passband in a fourth frequency range that at least partially overlaps with the third frequency range, the third bandpass filter and the fourth bandpass filter being electrically arranged in parallel relation to one another. 
   
     
     
         2 . The switchable diplexer of  claim 2 , wherein the plurality of switches comprise primary and secondary switches, and wherein the plurality of bandpass filters in a given group of bandpass filters share common secondary switches. 
     
     
         3 . The switchable diplexer of  claim 2 , wherein none of the plurality of bandpass filters in a given group share a common secondary switch with a bandpass filter in another group. 
     
     
         4 . The switchable diplexer of  claim 2 , wherein the groups of bandpass filters comprise two groups of two bandpass filters each, and wherein the switches comprise:
 two primary switches each connected to a communication link and configured to switch one of the two groups into the communication link; and   a pair of secondary switches for each group of bandpass filters, each pair of secondary switches having a first secondary switch coupled to one of the primary switches and a second secondary switch coupled to another one of the primary switches, each pair of secondary switches configured to select one of the two bandpass filters in their respective group.   
     
     
         5 . The switchable diplexer of  claim 2 , wherein the groups of bandpass filters comprise M groups of N bandpass filters each, and wherein the switches comprise:
 two primary switches each connected to a communication link and configured to switch one of the M groups into the communication link; and   a pair of secondary switches for each of the M groups of N bandpass filters, each pair of secondary switches having a first secondary switch coupled to one of the primary switches and a second secondary switch coupled to another one of the primary switches, each pair of secondary switches configured to select one of the N bandpass filters in their respective group.   
     
     
         6 . The switchable diplexer of  claim 5 , wherein when the primary switches are configured to select one of the groups of bandpass filters, other of the M groups of N bandpass filters are deselected by the primary switches, and further wherein each pair of secondary switches for the deselected groups of bandpass filters are set in a complementary configuration. 
     
     
         7 . The switchable diplexer of  claim 5 , wherein N is the same quantity for each of the M groups. 
     
     
         8 . The switchable diplexer of  claim 5 , wherein N is different for one or more of the M groups. 
     
     
         9 . The switchable diplexer of  claim 1 , wherein a first bandpass filter in at least one of the groups of bandpass filters has a high rejection frequency range that is at least partially overlapping a high rejection frequency range of a second bandpass filter in the at least one the groups of bandpass filters. 
     
     
         10 . The switchable diplexer of  claim 9 , wherein the high rejection frequency range is a predetermined frequency range of high rejection. 
     
     
         11 . A switchable diplexer, comprising:
 a first primary switch comprising a common terminal and M selectable terminals;   a first set of M secondary switches, each secondary switch comprising a common terminal and N selectable terminals, wherein the common terminal of each switch in the first set of M secondary switches is connected to one of the selectable terminals of the first primary switch;   a second primary switch comprising a common terminal and M selectable terminals;   a second set of M secondary switches, each secondary switch comprising a common terminal and N selectable terminals, wherein the common terminal of each switch in the second set of M secondary switches is connected to one of the selectable terminals of the second primary switch; and   a plurality of bandpass filters arranged in M groups of N bandpass filters, wherein:
 a first of said M groups comprising a first bandpass filter having a passband in a first frequency range and a second bandpass filter having a passband in a second frequency range that at least partially overlaps with the first frequency range, the first bandpass filter and the second bandpass filter being electrically arranged in parallel relation to one another, 
 a second of said M groups comprising a third bandpass filter having a passband in a third frequency range and a fourth bandpass filter having a passband in a fourth frequency range that at least partially overlaps with the third frequency range, the third bandpass filter and the fourth bandpass filter being electrically arranged in parallel relation to one another, and 
   each bandpass filter having a first terminal connected to one of the N selectable terminals of one of the first set of M secondary switches and a second terminal connected to one of the N selectable terminals of a corresponding one of the second set of M secondary switches.   
     
     
         12 . The switchable diplexer of  claim 11 , wherein bandpass filters in a given group of bandpass filters share a common switch of the first set of M secondary switches and a common switch of the second set of M secondary switches. 
     
     
         13 . The switchable diplexer of  claim 11 , wherein none of the plurality of bandpass filters in a given group share a common secondary switch with a bandpass filter in another group. 
     
     
         14 . The switchable diplexer of  claim 11 , wherein the M groups of N bandpass filters comprise two groups of two bandpass filters each, and wherein the switches comprise:
 the first and second primary switches each connected to a communication link and configured to switch one of the two groups into the communication link; and
 a pair of the first set and second set of secondary switches for each group of bandpass filters, each pair of secondary switches having a first secondary switch coupled to the first primary switch and a second secondary switch coupled to the second primary switch, each pair of secondary switches configured to select one of the two bandpass filters in their respective group. 
   
     
     
         15 . The switchable diplexer of  claim 11 , wherein when the primary switches are configured to select one of the M groups of N bandpass filters, and other of the M groups of N bandpass filters are deselected by the primary switches, and further wherein each pair of secondary switches for the deselected groups of bandpass filters are set in a complementary configuration. 
     
     
         16 . The switchable diplexer of  claim 11 , wherein N is the same quantity of bandpass filters for each of the M groups. 
     
     
         17 . The switchable diplexer of  claim 11 , wherein N is a different quantity of bandpass filters for one or more of the M groups. 
     
     
         18 . The switchable diplexer of  claim 11 , wherein the number of N selectable terminals of a switch pair in the first and second set of M secondary switches is equal to or greater than the number of bandpass filters in a group of bandpass filters corresponding to that switch pair. 
     
     
         19 . The switchable diplexer of  claim 11 , wherein the number of N selectable terminals of a switch pair in the first and second set of M secondary switches is greater than a number of bandpass filters in a group of bandpass filters and at least one of the N selectable terminals of each secondary switch is connected to a signal ground. 
     
     
         20 . The switchable diplexer of  claim 11 , wherein the at least one of the first and second bandpass filters has an identified high rejection frequency range that is at least partially overlapping an identified high rejection frequency range of the other of the first and second bandpass filters in the group.