Date Period - This week

Anonymous here is an example on how you can add this and prev week:

Date Period = 
VAR __today = TODAY()
VAR __thisWeek = 
    CALENDAR ( 
        __today - ( WEEKDAY( __today ) - 1 ), 
        __today + 7 - ( WEEKDAY ( __today ) ) 
    )
VAR __prevWeek = 
    CALENDAR ( 
        MINX ( __thisWeek, [Date] ) - 7, 
        MAXX ( __thisWeek, [Date] ) - 7 
    )
RETURN
UNION (
    ADDCOLUMNS (
        { __today },
        "Type", "Today",
    "Order", 1
    ),
    ADDCOLUMNS (
        { __today - 1 },
        "Type", "Yesterday",
        "Order", 2
    ),
    ADDCOLUMNS (
        __thisWeek,
        "Type", "This Week",
        "Order", 3        
    ),
    ADDCOLUMNS (
        __prevWeek,
        "Type", "Prev Week",
        "Order", 4     
    )
)