Get request to a .Net Web Api method with an (to me) incomprehensible parameter - what type of variable to use?

Question

ExtJS/Sencha

Kind.
The query parameters are as follows:
d1:04.04.2014
d2:04.04.2014
filter[0][field]:tp
filter[0][data][type]:string
filter[0][data][value]:tcac
page:1
start:0
limit:50
sort:[{"property":"data","direction":"DESC"}]
The method looks like this:
[HttpGet]
public dynamic DeficitByInterval(string d1, string d2,int start, int limit, int page)
{}
I can catch all parameters except "filter" parameter because I don't know what type should be used on the server.
PS This option is for server side filtering of ExtJs tables.
What type of variable should I use? string[ , , ] ?
Thank you.

Answer 1

The solution is unrealistically simple: in the filter settings you need to set encode: true and the parameters turn into Json