Authentication reader for motor vehicle opening element

An authentication reader (1B-1, 1B-2) for a motor vehicle opening element, said authentication reader (1B-1, 1B-2) comprising:

• a microcontroller (10B);
• at least one transmitter (20B);
• at least one matching circuit (30B-1, 30B-2);
• and
• a single primary antenna (L4) characterized by a working frequency,
• the matching circuit (30B-1, 30B-2) comprising switching means (M1;
• I1, I2) able to switch said matching circuit (30B-1, 30B-2) between a first mode in which the matching circuit (30B-1, 30B-2) permits the primary antenna (L4) to match a secondary antenna of an authentication device (2-1, 2-2) having a resonant frequency lower than the working frequency, and a second mode in which the matching circuit (30B-1, 30B-2) permits the primary antenna (L4) to match a secondary antenna of an authentication device (2-1, 2-2) having a resonant frequency higher than the working frequency,
• wherein the matching circuit (30B-1) comprises:
• a first branch (B1) connected to the transmitter (20B) via a first input terminal (E11) and to the primary antenna (L4) via an output terminal (S11) and comprising a first capacitor (C7), the primary antenna (L4) also being connected to ground (M), the matching circuit (30B-1) furthermore comprising a second capacitor (C8) connected to the output terminal (S11) and to the ground (M), and
• a second branch (B2) connected to the transmitter (20B) via a second input terminal (E21) and to the primary antenna (L4) at the output terminal (S11) and comprising a first capacitor (010), the matching circuit (30B-1) furthermore comprising a second capacitor (C11) connected to the output terminal (S11) and to the ground (M),
• and wherein the switching means are in the form of a switching branch connected in parallel with the primary antenna (L4) and comprising a switching capacitor (C13) connected in series with a switch (M1).